Economic Viability Research Articles

Advances in Catalytic Hydrogenation of Liquid Organic Hydrogen Carriers (LOHCs) Using High‐purity and Low‐purity Hydrogen

Liquid Organic Hydrogen Carriers (LOHCs) are emerging as a promising solution for global hydrogen logistics. The LOHC process involves two primary chemical reactions: hydrogenation for hydrogen storage and dehydrogenation for hydrogen reconversion. In the exothermic hydrogenation reaction, hydrogen‐lean compounds are converted to hydrogen‐rich compounds, storing hydrogen from various sources such as water electrolysis, fossil fuel reforming, biomass processing, and industrial by‐products. Conversely, hydrogen is extracted from hydrogen‐rich compounds through an endothermic dehydrogenation reaction and supplied to several hydrogenation utilization offtakers. This review article discusses the development trends in catalytic hydrogenation processes for various LOHC materials, including benzene, toluene, naphthalene, biphenyl, diphenylmethane, benzyltoluene, dibenzyltoluene, and N‐ethylcarbazole. It introduces references for catalytic hydrogenation processes utilizing both high‐purity and low‐purity (alternatively, mixed) hydrogen feedstocks, with particular emphasis on low‐purity hydrogen applications. The direct storage of hydrogen with minimal purification, using by‐product hydrogen and mixed hydrogen from hydrocarbon and biomass reforming, is crucial for the economic viability of this hydrogen carrier system.

Innovations in Sericulture an Advancements in Silk Production and Quality Improvement

Sericulture, the cultivation of silkworms for silk production, has a long and significant history, particularly in rural economies. In recent years, the industry has undergone transformative innovations that have enhanced efficiency, sustainability, and silk quality. This review explores key advancements in sericulture, focusing on technological innovations, genetic improvements, sustainable farming practices, and the role of biotechnology in reshaping the industry. Notable technological developments, such as automated silk reeling machines and climate-controlled rearing houses, have streamlined production, reducing labor demands while ensuring consistent silk quality. Additionally, digital monitoring systems now allow for real-time tracking of silkworm health and environmental conditions, empowering farmers with data-driven insights for better management. Genetic advancements, including selective breeding and genetic engineering, have led to high-yield, disease-resistant silkworm strains, significantly boosting silk output and quality. Moreover, innovations in producing naturally colored silk via genetic modification have minimized the need for chemical dyes, reducing the environmental footprint of the dyeing process. Sustainability has become a focal point, with organic farming methods, integrated pest management (IPM), and waste recycling practices becoming more widespread. These practices not only safeguard the environment but also enhance the economic viability of sericulture, benefiting rural communities and driving social development. Biotechnology has expanded the horizon of sericulture, enabling the engineering of silk proteins and the creation of transgenic silkworms for specialized medical and industrial applications. Overall, these advancements have transformed sericulture into a more efficient, sustainable, and economically viable industry, offering significant benefits to both global silk markets and rural livelihoods.

Innovative integration of sustainable technologies in educational programs: Fostering freshwater production and environmental preservation awareness

This study highlights the integration of sustainable desalination technologies into educational programs to raise awareness of freshwater production and environmental preservation. Through a comprehensive curriculum, students explore innovative methods such as pressure-retarded osmosis, multi-effect desalination, and seawater source heat pumps, all powered by renewable seawater thermal energy. The curriculum emphasizes the importance of reducing greenhouse gas emissions, lowering reliance on fossil fuels, and protecting aquatic ecosystems. Students engage in practical evaluations of energy efficiency, economic viability, and environmental impact. Sensitivity analyses are incorporated to help students identify critical factors affecting system performance and optimize operational conditions for various modes. Through hands-on experiments, students learn that components like the heat pump condenser contribute the most to energy loss (29 %), followed by the expansion valve (12 %), compressor (11 %), and seawater heat exchanger (8 %). Economic analyses reveal that while the heat pump condenser and seawater heat exchanger have the lowest financial impact (0.33 % and 2.48 %, respectively), the pressure-retarded osmosis and compressor units have the highest (100 % and 60.3 %, respectively). The findings demonstrate that an optimally designed desalination system can produce freshwater at 80 % lower costs compared to traditional plants, while also reducing carbon emissions by 15 %. Educational experiments also show that integrating pressure-retarded osmosis downstream of multi-effect desalination significantly reduces brine salinity and temperature, highlighting the system's potential for environmental sustainability. This approach not only fosters a deeper understanding of desalination technologies but also equips students with the tools to address future global water challenges.

PERFORMANCE AND ECONOMIC BENEFIT OF BROILER CHICKENS FED PEARL MILLET BASED DIETS SUPPLEMENTED WITH SYNTHETIC METHIONINE

The rising costs and inconsistent availability of conventional feed ingredients like maize in broiler chicken production have necessitated the exploration of alternative grains, such as pearl millet, which, when supplemented with synthetic methionine, could potentially enhance both performance and economic returns. This study which was conducted for a period of eight weeks assessed the effectiveness and economic viability of feeding broiler chickens diets containing pearl millet supplemented with synthetic methionine. Three hundred broiler chicks were randomly assigned to five dietary groups for both the starter and finisher phases, with each group containing sixty birds. The experiment followed a Completely Randomized Design (CRD) with three replications, each containing twenty birds. The diets for each group contained varying levels of DL methionine: 0.1%, 0.2%, 0.3%, 0.4%, and 0.5%, denoted as T1, T2, T3, T4, and T5 respectively. Although most performance metrics such as weight gain and feed intake did not exhibit significant differences among the groups, mortality rates showed a slight decrease with higher methionine inclusion. Economic analysis indicated that T1 had better Total Feed Cost (FC), and FC (₦/kg gain). The study concluded that pearl millet-based diets with synthetic methionine reduced mortality and proved cost-effective, offering a viable alternative for broiler chicken production.

Energy-efficient separation of a ternary azeotropic mixture via azeotropic reflux-induced sequences based on the intensified pressure-swing distillation

The recovery and separation of chloroform, acetonitrile and ethanol from waste water involving two azeotropes and a distillation boundary has emerged as a pivotal concern in the pursuit of environmental protection and resource conservation. Herein, the energy-efficient separation design of the ternary azeotropic mixture based on a triple-column pressure-swing distillation (TCPSD) process with five azeotropic reflux induced sequences is comprehensively investigated. The suitable operating pressure range of the distillation columns and the potential optimal distillation sequence is investigated based on the thermodynamic intrinsic probe. According to the optimal distillation sequence, further process intensification strategies are proposed to improve the thermodynamic efficiency encompassing the heat integration pressure-swing distillation (HI-PSD), heat pump assisted pressure-swing distillation (HP-PSD), and a combination of heat pump assisted and heat integration pressure-swing distillation (HPHI-PSD). It unveils the economic preeminence of the HI-PSD process, characterized by the lowest total annual cost (TAC) in a shorter payback period (3 to 7 years). Conversely, both the HP-PSD and HPHI-PSD processes exhibit superior environmental performance on CO2 emissions of 111.46 kg/h and 119.78 kg/h respectively, with the HP-PSD demonstrating prolonged economic viability and the HPHI-PSD showcasing heightened thermodynamic efficiency of a 65.12 % improvement. This study potentially provides a theoretical basis for devising industrial separation schemes for analogous pressure-sensitive ternary azeotropic systems.

Nutrient recovery in wastewater treatment plants through biosolids and struvite precipitation: Case study in Panama City

This work assesses the nutrient recovery potential in Panama City’s wastewater facilities. Nutrients can be recovered by using biosolids, which are currently dumped in landfills, and by precipitating struvite from waste streams. The economic viability of four types of struvite reactors was analyzed. The installation of struvite systems is not profitable for the current discharge limit of 10 mg/l for P. However, for P limits of 4 mg/l and below, struvite systems would generate significant revenue due to savings in the chemicals needed to remove the excess of P. For a P limit of 4 mg/l, the best struvite reactor presented a payback time of 10 years and a return on investment of 13.68 %. It is concluded that in Panama, as in the rest of Latin American countries, nutrient discharge standards are currently too loose for struvite systems to become viable. Meanwhile, the use of biosolids is of particular interest as the standards for their use are already well developed. The use of biosolids from Panama City could supply 1.6 % of the consumption of fertilizers in the country. It was found that the quality of the biosolids that are produced in the region is satisfactory, and that the demand from potential users can be improved through composting the material.

Carbon footprint and economic viability assessment of recycling sewage sludge in sintered brick manufacturing route

Carbon footprint and economic viability assessment of recycling sewage sludge in sintered brick manufacturing route

On the role of the Bernoulli force in stuck pipe during oil and gas well drilling

Stuck pipe is one of the most prevalent and costly complications encountered during drilling operations in the oil and gas industry. It represents a significant challenge, contributing to delays and increased financial costs that cumulatively amount to billions of dollars annually. Understanding and addressing the root causes of pipe sticking are crucial for minimizing these adverse impacts. This paper provides a comprehensive analysis of the various factors contributing to stuck pipe incidents, highlighting both traditional and newly identified mechanisms. Key factors leading to pipe sticking include mechanical issues such as rock particles drilled out during the process, inadequate well cleanup, wellbore instability, and differential sticking forces, which are primarily due to the disparity between hydrostatic pressure and formation pressure. These issues are particularly prevalent in horizontal or inclined wells, where the dynamics of drilling differ significantly from vertical wells, exacerbating the risks of pipe sticking. The occurrence of stuck pipe not only increases the duration of drilling operations but also significantly escalates the associated costs, thereby impacting the overall economic viability of drilling projects. A novel factor contributing to stuck pipe is the Bernoulli force, a phenomenon that has been discussed in detail in this article. The Bernoulli force acts perpendicular to the flow axis from the edges towards the center of the flow. In the context of cylindrical flow within a wellbore, this force is magnified as the density difference between the drilled rock particles and the drilling fluid increases, along with the diameter of the mechanical cuttings. As a result, the Bernoulli force facilitates the migration of drilled rock particles towards the flow center, leading to an accumulation that increases local resistance due to friction. This intensified resistance can significantly contribute to the occurrence of a stuck pipe, presenting a new challenge for drilling operations that must be addressed. This paper discusses the comprehensive mechanisms of stuck pipe, including the differential and mechanical factors, and provides an in-depth analysis of these aspects. The study emphasizes the importance of understanding these factors to develop effective strategies for prevention and mitigation. By exploring the key features necessary to minimize the risks associated with differential and mechanical sticking, this article offers valuable insights into improving well drilling practices. The findings underscore the need for thorough well cleanup, effective management of wellbore instability, and a nuanced understanding of pressure dynamics to prevent stuck pipe incidents. The paper concludes with recommendations for industry practices and further research to mitigate the impact of stuck pipe on drilling operations.

A Techno-Economic Analysis of a Hybrid Microgrid System in a Residential Area of Bangladesh: Optimizing Renewable Energy

In the face of a significant power crisis, Bangladesh is turning towards renewable energy solutions, a move supported by the government’s initiatives. This article presents the findings of a study conducted in a residential area of Pabna, Bangladesh, using HOMER (Hybrid Optimization of Multiple Energy Resources) Pro software version 3.14.2. The study investigates the feasibility and efficiency of a grid-connected hybrid power system, combining photovoltaics (PV), a biomass generator, and wind energy. The simulation produced six competing solutions, each featuring a distinct combination of energy sources. Among the configurations analyzed, the grid-connected PV–biomass generator system emerged as the most cost-effective, exhibiting the lowest COE at USD 0.0232, a total net present cost (NPC) of USD 321,798.00, and an annual operating cost of USD 6060.59. The system presents a simple payback period of 9.25 years, highlighting its economic viability. Moreover, this hybrid model significantly reduces CO2 emissions to 78,721 kg/year, compared to the 257,093 kg/year emissions from a solely grid-connected system, highlighting its environmental benefits. Sensitivity analyses further reveal that the system’s performance is highly dependent on solar irradiance, indicating that slight variations in solar input can significantly impact the system’s output. This study underscores the potential of integrating multiple renewable energy sources to address the power crisis in Bangladesh, offering a sustainable and economically viable solution while also mitigating environmental impacts.

Cost-benefit analysis of implementing a solar powered water pumping system – A case study

Solar-powered water driving scheme (SPWDS) has been successfully employed as a practical solution to guarantee reliable water supply in various hilly regions without electrical infrastructure. The Water Supply Systems / Schemes (WSS) focus on using pumping systems for delivering potable water to the community but face practical difficulties and financial hurdles at different implementation stages. These challenges encompass the practical complexities, the absence of non-renewable energy sources, and ongoing expenses for consumable and non-consumable items incurred during the water project's execution and maintenance. The present research study evaluates the performance of four water supply systems in Nepal which use solar energy as their primary power source. The key performance indicators are assessed, including the functionality index for facility distribution. Additionally, the research aims to evaluate the feasibility of transitioning from non-renewable to sustainable renewable energy source to achieve net zero energy consumption. This evaluation concentrates explicitly on calculating the cost-effectiveness index as a key metric. A proportional analysis is undertaken to evaluate the cost-benefit of the SPWDS, considering both the potential advantages and challenges associated with these initiatives. The present study affirms the technical feasibility and economic viability of operating a WSS using renewable and eco-friendly solar energy as the power source. This finding opens avenues for reducing energy consumption and contributes significantly to developing a policy framework to for tapping solar energy.

Deflection estimation of reinforced concrete beams using long-gauge optic sensors

Deflection is a crucial indicator in structural health monitoring, directly impacting the service life, safety, and economic viability of structures. However, current indirect methods for measuring deflection, such as multi-element FBG sensors or accelerometers, often have limitations. While they may be suitable for flexure-dominated reinforced concrete (RC) specimens in the elastic stage, they neglect the significant influence of nonlinearity and shear deformation. This paper introduces a new approach for estimating the deflection of reinforced concrete (RC) beams using distributed long-gauge optic sensors. The method tackles the limitations of current methods by incorporating the crucial factors of shear deformation, neutral axis position variation and shear stiffness degradation. Experimental studies are first conducted to validate the accuracy and stability of long-gauge optic sensors in small-scale RC members. Algorithms are then utilized the measurement data to estimate the deflection. The results demonstrate the excellent performance of long-gauge optic sensors in measuring shear deformation and vertical deflection of RC beams, as evidenced by comparisons with LVDT measurements. Additionally, a method for decoupling flexural and shear deformation is proposed. This method offers a preliminary assessment of the reinforced concrete (RC) beam type by quantifying the relative significance of shear deformation.

Impacts of Polyvinyl Alcohol and Chitosan-Modified Biochar on the Anaerobic Digestion of Sewage Sludge and Valuable Resource Recovery

The accumulation of organic dyes and heavy metals (HMs) in sewage sludge (SS) after wastewater treatment is a significant problem due to the non-degradable nature of these pollutants. Moreover, the simultaneous removal of HMs and dyes in the complex process of SS treatment, such as anaerobic digestion (AD), has become attractive. HMs and dyes present in SS can have a detrimental effect on anaerobic digesters. These pollutants not only inhibit the production of methane, which is crucial for biogas generation, but also affect the stability of AD treatment, which can result in failure or inadequate performance of the AD process. This review highlights a novel method of removing HMs and dyes from the AD process of SS through the use of biochar modified with polyvinyl alcohol (PVA) and chitosan (CTS). The applications of conventional biochar have been limited due to poor adsorption capacity. However, modification using PVA/CTS composites enhances properties such as surface functional groups, adsorption capacity, porosity, surface area selectivity, and stability. Furthermore, this modified version can function as an additive in AD of SS treatment to boost biogas production, which is a viable source for heat generation or electricity supply. In addition, the digestates can be further processed through plasma pyrolysis for the removal of HMs and dyes bound to the modified biochar. Plasma pyrolysis generates two major products: syngas and slag. The syngas produced can then be used as a source of hydrogen, heat, and electricity, while the slag can potentially be reused as an AD additive or as a biofertilizer in the agricultural sector. Additionally, this study addresses the challenges associated with this integration and biochar modifications, and offers an outlook on understanding the interactions between the modified biochar properties, microbial dynamics, and the presence of micropollutants to ensure the economic viability and scalability of this technology. This comprehensive review provides insights into the potential of PVA/CTS-modified biochar as an effective additive in AD systems, offering a sustainable approach to SS treatment and valuable resource recovery.

Investment in CCUS under technical uncertainty considering investor's risk aversion: An exotic compound real-options approach

Carbon capture, utilization, and storage (CCUS) technology is effective and value-adding solution for reducing emissions. However, the development and commercialization of these technologies are challenging due to high investment costs and several uncertainties. This study develops a novel comprehensive real-options-based model to evaluate investment in CCUS projects considering the technical risk and the investor's risk aversion. This study proposed an exotic compound real options model that combines American and barrier options. First, applying the Poison process, the technical risk is explicitly modeled. Secondly, the investor's risk aversion is defined as a barrier level for the barrier option part of the proposed model. Thirdly, the value of the project is evaluated through the exotic compound real option. Finally, we assess the economic viability of the project under multiple scenarios. The results of implementing the model for a real case show that the integrated technical risk assessment and the barrier option appropriately address investors' risk aversion. Furthermore, the comparison indicates that the proposed compound real options model is more effective than the traditional NPV (Net Present Value). Regarding policymaking, the results reveal that setting an appropriate carbon tax that considers the costs of carbon capture would be more beneficial. Further, the model provides investors helpful guidance to make proper investment decisions for CCUS technology projects under uncertainties.

Nordic perspectives on the emerging biochar business

Biochar production offers various benefits related to climate change mitigation, circular economy, waste management, renewable energy, and reduced dependency on fossil carbon. Despite these advantages, the biochar market in the Nordic region is still developing. This study explores the current state and future potential of the Nordic biochar market, identifying existing and potential market segments, the role of biochar and its co-products, and factors affecting market growth. The study involved an online survey conducted in 2021, targeting key Nordic biochar stakeholders, including business actors, academic researchers, and other relevant groups (N = 72, representing 64 organizations). The findings reveal that the Nordic biochar market is in its nascent stages, with producers often considering biochar production as a side business. The market faces challenges such as inadequate legal and policy support, limited public awareness, lack of established norms, and uncertainties regarding profitability, technological efficiency, and market potential. However, the industry holds substantial growth potential due to its environmental and climate benefits, provided that current barriers are overcome. Key applications of biochar include carbon removal, water filtration, soil remediation, landscaping, and composting. Additionally, co-products such as energy-dense gases and bio-oil have the potential to enhance the economic viability of biochar production. To facilitate market development, integrating established scientific knowledge into industry standards and policies is crucial. The study underscores the importance of biochar networks and associations in advocating for industry development and highlights the need for enhanced collaboration among stakeholders to overcome existing barriers. Additionally, focused research on the varied applications of biochar is needed, with an emphasis on thoroughly evaluating its environmental, economic, and social impacts.

The influence of selected grain size fractions of coal fly ash on properties of clay-cement mortars used for the flood levees construction

This study examines the influence of different grain size fractions of coal fly ash on the properties of clay-cement mortars used in flood levee construction. Dry aerodynamic separation and mesh sieving were used to obtain ultrafine, fine, and medium fractions of high-calcium and silica fly ash. The experimental results reveal that the rheological properties of fresh mortars are significantly influenced by these fractions. High-calcium fly ash mortars exhibit high reactivity and rapid increase in viscosity, with finer fractions showing the highest reactivity. Silica ashes show increased reactivity in the later stages of suspension hardening. Their spherical shape contributes to reducing internal friction during flow in initial technological operations. Furthermore, the compressive strength of hardened mortars improves as the particle size decreases for both ashes, resulting in a dense and uniform microstructure. The separation and fractionation of fly ashes contribute to the obtaining of fractions that influence the parameters of clay-cement suspension application on different scales. The results show the potential benefits of ash separation, which can bring advantages in terms of economic viability, engineering performance, and ecological sustainability.

PSVII-29 Integrating hybrid rye into organic pig production to reduce feed and bedding costs

Abstract An obstacle to profitable organic swine production is the high cost of feed and bedding. We evaluated whether growing hybrid rye for organic feed and bedding for pigs was economically viable by replacing corn with hybrid rye and evaluating pig growth performance and feed and bedding costs. Hybrid rye was grown on certified organic land at WCROC in 2022 and 2023. Rye grain and straw were used in a feeding trial with pigs raised according to the National Organic Standards. The animal trial consisted of three replicates. Each replicate included 100 pigs in two pens (Control vs. Rye, 50 pigs/pen) in a bedded hoop barn. Control pigs were fed corn soybean meal-based diets and Rye pigs were fed diets with 50% of corn in the control diets replaced by hybrid rye. Each replicate lasted for about 12 wk until pigs reached market weight (120 kg). Pigs were weighed individually at the beginning, every 4 wk thereafter, and at the conclusion of the study. Feed disappearance was recorded on a pen basis at the time of weighing pigs. Growth performance[average daily gain(ADG), average daily daily feed intake (ADFI), and Gain: Feed] was calculated for each weigh period. Carcass weight was recorded at harvest and dressing percent was calculated for each pig. Bedding usage was recorded for each pen (Control pen = wheat straw, Rye pen = rye straw) and average usage for each pig was calculated. Growth performance and bedding usage data were analyzed using the Proc Glimmix Procedures of SAS, with dietary treatment as the fixed effect, replicate as the random effect, and pen as the experimental unit. Production costs were set at $239/ha for organic rye grain and $20/ha for rye straw baling according to the FINBIN Database, and the unit costs ($/kg) were calculated based on yield for each year. Prices for organic corn, soybean meal, base mix, wheat straw, and market pigs were based on market prices (Table 1). Yield of organic hybrid rye grain at WCROC was 1,070 and 712 kg/ha in 2022 and 2023, respectively, with corresponding rye straw yield being 661 and 367 kg/ha. The reduction in rye yield in 2023 was considered due to drought. No difference was detected in growth performance, dressing percent, or bedding usage between Control and Rye pigs (all P > 0.19; Table 1). Replacing 50% of corn with hybrid rye saved $9.6/pig in 2022, but cost $7.20/pig more for feed in 2023, due to changes in hybrid rye grain yield. Savings on bedding were $15.40 and $13.20/pig for 2022 and 2023, respectively. Results indicate that replacing 50% of corn with hybrid rye in feed did not negatively affect growth performance of pigs raised organically, but the economic viability of integrating hybrid rye into organic pig production may depend on crop yield.

Economic Evaluation of Conservation through Use of an Araucaria angustifolia Provenance and Progeny Test.

Araucaria angustifolia is a species known for its valuable wood and nuts, but it is threatened with extinction. The plantation of forests for genetic resource conservation is a complementary strategy designed to reduce the species' genetic variability loss. This study aimed to evaluate the technical and economic viability of A. angustifolia for genetic conservation through use. The analyzed provenance and progeny trial was established in 1982 in Itapeva, Brazil. It was structured using a compact family blocks design with 110 open-pollinated progenies from five natural populations, three replicates, ten plants per subplot, and 3.0 m × 2.0 m spacing. After 33 years, the trial was evaluated for total height, diameter at breast height, wood volume, and survival. The variance components and genetic parameter estimates were performed using Restricted Maximum Likelihood/Best Linear Unbiased Prediction methods (REML/BLUP) methods with the Selegen software (version 2014). The production and management scenarios were obtained using the SisAraucaria software (version 2003). Sensitivity analysis and economic parameter estimates were obtained through various economic evaluation methods using the Planin software (version 1995). In general, the genetic parameters indicated that the population has enough variability for both conservation and breeding purposes, suggesting technical viability for the establishment of a seed orchard. The economic parameters indicated that the commercialization of wood and araucaria nuts proved to be more profitable than wood production by itself. In conclusion, araucaria genetic conservation through use is a technically and economically viable ex situ conservation strategy.

Enhancing socioeconomic sustainability in glass wall panel manufacturing: An integrated production planning approach

While conventional production planning approaches prioritize short-term efficiency and economic gains, the sustainability development objectives emphasize a holistic perspective, integrating eco-friendly practices, social responsibility, and economic viability. Nevertheless, the existing literature overlooks a gap in understanding the role of socio-economic factors in labor-intensive production processes. In this regard, this research aims at investigating the impact of social factors, such as labor skill level and experience, on production planning, with a specific focus on glass wall panel manufacturing. The research integrates sustainability socioeconomics, as embodied by an empirically developed labor learning curve, with the MINLP (Mixed-Integer Nonlinear Programming) scheduling model. The results show that the integrated socio-economic scheduling approach outperforms traditional scheduling approach, reducing idle time up to 43% and promoting more balanced production distribution. Despite slightly higher upfront production costs, the integrated model offers long-term cost savings through reduced idle time and overtime, making it a viable option for companies seeking to improve productivity and worker satisfaction. The implementation of this work is recommended to maintain a sustainable, safe, and healthy work environment while also considering long-term economic benefits rather than short-term profits.

Theoretical investigation of sustainable CO2 electroreduction to high-value products utilizing N-doped/BN-modified Triphenylene-Graphdiyne catalysts

The potential of carbon-based triphenylene-graphdiyne (tpGDY) and its derivatives for the electrochemical CO2 reduction reaction (eCO2R) was comprehensively explored using density functional theory (DFT) calculations. Six variants were studied: pristine tpGDY, tpGDY-BN, tpGDY-N01, tpGDY-N02, tpGDY-N08, and tpGDY-BN-B01. Pristine tpGDY, tpGDY-BN, and tpGDY-N08 exhibited exceptional catalytic activity, efficiently converting CO2 into CO and HCOOH without external energy input. Significantly, N-doped tpGDY catalysts incorporating sp2-hybridized nitrogen atoms at the acetylenic sites (tpGDY-N01 and tpGDY-BN-N01) demonstrated remarkable electrocatalytic activity for the targeted conversion of CO2 to CH3OH. This outstanding performance is further corroborated by the low limiting potentials of −0.18 V and −0.27 V for tpGDY-N01 and tpGDY-BN-N01, respectively, highlighting their economic viability. Furthermore, the feasibility of C2 production (e.g., C2H5OH, C2H4 and C2H6) through C–C coupling of *CHO+*CO intermediate was investigated for tpGDY-N01 and tpGDY-BN-N01. DFT calculations suggest these pathways are achievable but require potentials of 0.84 V and 0.71 V for tpGDY-N01 and tpGDY-BN-N01, respectively. This study demonstrates the efficacy of N-doped tpGDY as a metal-free electrocatalyst for CO2 reduction, enabling the generation of both C1 and C2 products. This discovery holds significant promise for the advancement of sustainable CO2 conversion technologies.

Black titanium oxide: synthesis, modification, characterization, physiochemical properties, and emerging applications for energy conversion and storage, and environmental sustainability.

Since its advent in 2011, black titanium oxide (B-TiOx) has garnered significant attention due to its exceptional optical characteristics, notably its enhanced absorption spectrum ranging from 200 to 2000 nm, in stark contrast to its unmodified counterpart. The escalating urgency to address global climate change has spurred intensified research into this material for sustainable hydrogen production through thermal, photocatalytic, electrocatalytic, or hybrid water-splitting techniques. The rapid advancements in this dynamic field necessitate a comprehensive update. In this review, we endeavor to provide a detailed examination and forward-looking insights into the captivating attributes, synthesis methods, modifications, and characterizations of B-TiOx, as well as a nuanced understanding of its physicochemical properties. We place particular emphasis on the potential integration of B-TiOx into solar and electrochemical energy systems, highlighting its applications in green hydrogen generation, CO2 reduction, and supercapacitor technology, among others. Recent breakthroughs in the structure-property relationship of B-TiOx and its applications, grounded in both theoretical and empirical studies, are underscored. Additionally, we will address the challenges of scaling up B-TiOx production, its long-term stability, and economic viability to align with ambitious future objectives.