H2 Gas Research Articles

Sustainable Synthesis of Substituted 1,3,5-Triazines by [ONO]-Pincer-Supported Nickel(II) Complexes via an Acceptorless Dehydrogenative Coupling Strategy.

A facile, cost-effective, and sustainable synthesis of substituted triazines from primary alcohols by newly synthesized nickel pincer-type complexes (1-3) has been described. Herein, we report the synthesis of a set of three well-defined Ni(II) O^N^O pincer-type complexes, structurally characterized by analytical, spectral, and X-ray diffraction techniques. Further, the nickel complexes are explored as efficient catalysts (4 mol %) for the construction of 2,4,6-substituted 1,3,5-triazines from readily available alcohols via an acceptorless dehydrogenative coupling (ADC) strategy. A wide range of substituted triazine derivatives (33 examples) has been synthesized from the coupling of alcohols and benzamidine/guanidine hydrochloride with a maximum isolated yield of 92% under mild conditions, with eco-friendly H2O and H2 gas as the only byproducts. A plausible mechanism has been proposed based on a sequence of control experiments. Interestingly, the short synthesis of the antiulcer drug irsogladine and the large-scale synthesis of 2,4-diphenyl-6-(p-tolyl)-1,3,5-triazine highlight the convenience of the current methodology.

Anodic Hydrogen Generation from Benzaldehyde on Au, Ag, and Cu: Rotating Ring-Disk Electrode Studies

Abstract Aldehydes are selectively oxidized to carboxylates on group 11 metals at low potentials (<0.4 V vs. RHE) in alkaline media. This process can occur by a pathway that generates H2 gas from the aldehyde, known as electro-oxidative dehydrogenation (EOD) or anodic hydrogen production. The EOD process occurs with transfer of only one electron per aldehyde, whereas typical oxidation with discharge of hydrogen to form water is a two-electron process. Here, we study the catalytic activity and selectivity toward H2 of Au, Ag, and Cu electrodes using benzaldehyde with rotating disk and ring-disk electrode (RDE/RRDE) techniques. The average number of electrons per benzaldehyde molecule obtained via H2 detection by RRDE agrees with that obtained via Koutecký-Levich analysis conducted at various rotation rates. We find that Au and Ag have much higher H2 and benzoate formation rates than Cu, but that Cu can perform the reaction at about 0.2 V lower overpotentials. On all three materials, benzaldehyde oxidation has high selectivity to anodic H2 (one-electron pathway) below ~0.5 V vs. RHE, but, with increasing potential, the selectivity shifts to H-oxidation forming water (two-electron pathway).

Bimetallic PdPt nanoparticle-incorporated PEDOT:PSS/guar gum-blended membranes for enhanced CO2 separation.

To address the escalating demand for efficient CO2 separation technologies, we introduce novel membranes utilizing natural polymer guar gum (GG), conjugate polymer (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) PEDOT:PSS, and bimetallic PdPt nanoparticles. Bimetallic PdPt nanoparticles were synthesized using the wet chemical method and characterized using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques. The morphologies, chemical bonds, functional groups, and mechanical properties of the fabricated membranes were characterized using various techniques. Through meticulous fabrication and characterization, the binary blended membranes demonstrated enhanced homogeneity and smoothness in their structure, attributed to the interaction between the polymers, and superior CO2 permeability due to the amphiphilic nature of the PEDOT:PSS polymer. Gas separation experiments performed using H2, N2, and CO2 gases confirmed that the 20% PEDOT:PSS/GG blended membranes showed the best performance with sufficient mechanical properties. Moreover, the results demonstrated an increase of 172% in CO2 permeability and 138% in CO2/H2 selectivity, respectively. Furthermore, integrating bimetallic PdPt nanoparticles provided an additional 197% increase in CO2/H2 selectivity, owing to the unique catalytic activities of noble metal nanoparticles. The study not only underscores the transformative potential of polymer blending and noble metal engineering, but also highlights the significance of using natural polymers for sustainable environmental solutions.

Performance Assessment of a JF-CP-TFET for Hydrogen Gas Sensing Applications

Abstract In this paper, a junction-free charge plasma tunnel field-effect transistor (JF-CP-TFET) is proposed and analyzed for the first time to sense hydrogen (H2) gas. Using junction-free and charge-plasma approaches, the proposed JF-CP-TFET-based sensor minimizes random dopant fluctuations, a large thermal budget requirement, and complex processes in the semiconductor sensor production process. The sensing performance of the JF-CP-TFET-based gas sensor is demonstrated by analyzing changes in the work function of the gate of palladium (Pd) catalytic metals, which are proportional to the pressure of H2 gas exposed at the metal gate surface. The presence of H2 gas has been demonstrated by variations of the DC/AC parameters of the proposed sensor, such as carrier concentration, energy band, electric field, transfer characteristics, threshold voltage (VTh), and subthreshold swing (SS). The sensitivity of the JF-CP-TFET-based sensor has been evaluated in terms of drain current (IDS), ION/IOFF ratio, VTh, and SS change in the presence and absence of H2 gas molecules. The sensing capabilities of the proposed JF-CP-TFET-based gas sensor demonstrate that it could potentially be employed for H2 gas detection with excellent sensitivity and reliability.

Novel gas sensing mechanisms of Pd and Rh-doped h-BN monolayers for detecting dissolved gases (H2、CH4、and C2H4) in transformer oil

Detecting dissolved gases in transformer oil is crucial for assessing the operational status of transformers. The gas composition in transformer oil can reflect the health status of the equipment and help identify potential failure risks in a timely manner. Based on density functional theory (DFT), Pd and Rh atoms were doped into the h-BN monolayer, and the most stable adsorption structures for each were first explored. Then, the sensing performance of the Pd-doped and Rh-doped h-BN monolayers for H2, CH4, and C2H4 gases was analyzed. The results indicate that Pd-BN and Rh-BN exhibit enhanced sensitivity to H2 and C2H4 gases compared to pristine h-BN. However, they show poor adsorption characteristics for CH4. Both Pd-BN and Rh-BN demonstrate strong chemisorption for H2 and C2H4. In contrast, CH4 adsorption is predominantly physisorbed. The desorption time of H2 from Pd-BN at 398 K is 164 s, reflecting its excellent desorption performance. Additionally, Pd-BN and Rh-BN monolayers exhibit exceptional C2H4 capture capabilities, with adsorption energies of −1.697 eV and −2.188 eV, respectively, indicating their potential as C2H4 gas adsorbents. These findings provide theoretical insights for selecting materials for dissolved gas detection in oil and lay the groundwork for the development of Pd-BN and Rh-BN-based gas sensors.

Magnetite–poly-1H pyrrole dendritic nanocomposite seeded on poly-1H pyrrole: A promising photocathode for green hydrogen generation from sanitation water without using external sacrificing agent

Abstract The Fe3O4 magnetite–poly-1H pyrrole dendritic nanocomposite seeded on additional poly-1H pyrrole film, denoted as Fe3O4-P1HP/P1HP, is synthesized by oxidative polymerization utilizing (Fe(NO3)3·5H2O for the pyrrole monomer. The resulting nanocomposite exhibits a notable bandgap of 1.97 eV and demonstrates broad optical absorption up to 625 nm. The structure of each particle consists of numerous smaller internal particles, which are composed of nanofibers of approximately 2.0 nm in length and porous structures of around 5.0 nm. These porous structures cluster together to form a larger configuration, with an overall diameter of ∼230 nm and a length of approximately 300 nm, giving the composite a nano-cactus-like appearance. The fabricated Fe3O4–P1HP/P1HP photocathode is inserted into a three-electrode cell to facilitate green hydrogen production from sanitation water without the need for any external sacrificial agent. The performance of H2 gas generation is assessed by measuring the photocurrent density (J ph) under light, which serves as an indicator of the efficiency of hydrogen production. The J ph value reaches −0.23 mA/cm² under light conditions. The highest J ph values of −0.164 and −0.158 mA/cm² are observed at wavelengths of 340 and 440 nm, respectively. However, as the wavelength reaches 540 nm, the J ph value decreases to −0.134 mA/cm² and drops to its lowest point of −0.128 mA/cm² at 730 nm, which is comparable to the dark current (J o). The fabricated photocathode demonstrates a promising hydrogen generation rate of 90 µmol/h cm², reflecting its potential for commercial applications. The combination of this impressive hydrogen production rate, along with the photocathode’s cost-effectiveness and straightforward fabrication process, suggests that this technology could be commercially viable for converting sanitation water into hydrogen gas.

Regional and seasonal impact of hydrogen propulsion systems on potential contrail cirrus cover

The decarbonization of air transportation requires novel propulsion concepts in order to replace fossil kerosene powered gas turbines. Within various options, H2 based propulsion is one of the most promising candidates, at least for regional and short haul routes. However, despite the potential to reduce CO2 emissions to zero, those aircraft can still have a significant climate impact due to increased contrail formation caused by higher water emission when using H2 as a propellant. In order to understand potential changes in the climate impact of H2 powered air traffic, it is crucial to evaluate how the potential for contrail formation and the potential contrail cirrus cover would change under representative atmospheric conditions. To this end, we developed a tool which uses several years of meteorological reanalysis data (ERA-5 and MERRA-2) in combination with contrail formation conditions adjusted to H2 gas turbine and H2 Fuel Cell propulsion in order to investigate their regional and seasonal variation. Contrail formation conditions for three different propulsion settings (kerosene gas turbine, H2 gas turbine and H2 fuel cell) are calculated to obtain global statistics of potential contrail cover and potential contrail cirrus cover over 12 years. For H2 based propulsion contrails are more likely to form due to the increased water vapor emission. However, this does not necessarily translate into the climatically relevant potential for contrail cirrus formation. Focusing on three hot spots of regional air traffic, we find that the difference between kerosene and H2 scenarios has a strong systematic dependency on season, altitude and latitude. Maximum differences in potential contrail cirrus cover are found in the transition region from typically no-contrail to contrail forming conditions at a potential contrail cover around 50%. In contrast, less to no difference in potential contrail cirrus cover is found at very high (close to 100%) or rather low potential contrail cover. This study demonstrates, that the question whether H2 powered air traffic produces more climate relevant contrail cirrus can not be parameterized by a simple factor but rather strongly depends on the propulsion type, season, region and flight altitude.

Comprehensive overview of detection mechanisms for toxic gases based on surface acoustic wave technology

Identification and detection of toxic/explosive environmental gases are of paramount importance to various sectors such as oil/gas industries, defense, industrial processing, and civilian security. Surface acoustic wave (SAW)-based gas sensors have recently gained significant attention, owing to their desirable sensitivity, fast response/recovery time, wireless capabilities, and reliability. For detecting various types of targeted gases, SAW sensors with different device structures and sensitive materials have been developed with diversified working mechanisms. This paper is focused on overviewing recent advances in working mechanisms and theories of dominant sensitive materials and key mechanisms/principles for targeting various gases in the realm of SAW gas sensors. The basic sensing theories and parameters of SAW gas sensors are briefly discussed, and then the major influencing factors are systematically reviewed, including the effects of various sensitive layer materials, temperature/humidity, and UV illumination on the overall performance of SAW gas sensors. We further highlight the relationships and adsorption/desorption principles between sensing materials and key targeted gases, including NH3, NO2, H2S, explosive gases of H2, and 2,4,6-trinitrotoluene, and organic gases of isopropanol, ethanol, and acetone, as well as others gases of CO, SO2, and HCl. Finally, we discuss key challenges and future outlooks in designing methodologies of sensing materials and enhancing the performance of SAW gas sensors, offering fundamental guidance for developing SAW gas sensors with good sensing performance.

Effects of adding copper to bismuth titanate for photocatalytic hydrogen production

In this work, pure and copper-doped bismuth titanate perovskites were synthesized using the modified amorphous citrate method to evaluate the influence of the dopant on the material's structure and its efficiency as a catalyst. X-ray diffraction method has been employed for the analysis of the crystal structure while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques were used to examine the material's morphology. Electron dispersion spectroscopy (EDS) was also employed to confirm the doping of the material. The doped material exhibited a bandgap within the visible region calculated using the Tauc plot from UV-Vis diffuse reflectance spectroscopy. The dopant influenced the emergence of secondary bandgaps with considerably lower values than the pure materials, directly impacting the photocatalytic performance of hydrogen gas (H2) production. The highest H2 gas production occurred in the doped and more crystalline sample. Comparing these results with other studies, it can be concluded that copper is a metal with great potential as a dopant for the development of bismuth titanate-based catalysts.

Microwave-assisted Synthesis of Pyrroles, Pyridines, Chromenes, Coumarins, and Betti Bases via Alcohol Dehydrogenation with Chroman-4-one Amino Ligands

: This study outlines the development of a novel approach utilizing microwave assistance for the alcohol dehydrogenative reaction. The process is catalyzed by manganese (II) and cobalt (II) in conjunction with chroman-4-one amino ligands. This research introduces a unique catalytic system capable of synthesizing various heterocyclic compounds, including pyrroles, pyridines, Betti bases, chromenes, and coumarins via alcohol dehydrogenation. The synthesis involved the preparation and characterization of a series of chroman- 4-one amino ligands (C1-C6) using standard analytical techniques. These ligands, in combination with MnCl2‧4H2O and CoCl2, demonstrated remarkable catalytic activity, effectively driving alcohol dehydrogenation. The catalytic cycle was initiated by the in-situ formation of metal complexes with the ligands during the reaction. Characterization using ESI-MS confirmed the presence of metal complexes (Int-1) and other intermediates (Int-II and Int-III) throughout the catalytic cycle. Additionally, the controlled experiment corroborated the efficacy of the catalytic system, evidenced by the evolution of H2 gas.

Optimization of Al2O3 shell thickness on SnO2 nanowires for realization of sensitive and selective H2 sensing

Detection of highly explosive H2 gas is a critical safety issue. Herein, using a vapor-liquid-solid growth mechanism, SnO2 nanowires (NWs) were prepared, after which Al2O3 shells (1.9, 3.3, 4.5, and 6.1 nm) were deposited on synthesized SnO2 NWs by atomic layer deposition. Based on characterization studies, C-S NW structures with a crystalline SnO2 core and amorphous Al2O3 shell were successfully formed. Based on H2 gas sensing measurement, SnO2-Al2O3 (4.5 nm) C-S NWs exhibited a high response of 152.54 to H2 (10 ppm) at 350°C. Furthermore, they showed excellent selectivity, where response to H2 gas (10 ppm) was more than 33 times higher than that to NO2 gas (10 ppm). Additionally, they displayed excellent repeatability as well as long-term stability in detection of low-concentration H2 gas. The improved H2 sensing capability was related to the high base resistance, the formation of the SnO2-Al2O3 heterojunction, the optimization of the Al2O3 shell thickness on SnO2 NWs, and the partial reduction of SnO2 and Al2O3 in an H2 gas atmosphere. This study sheds light on the development of H2 sensors based on present material.

Two-in-One Ni2+-Doped CsPbBr3 Nanocrystals Enabling Acceptorless Photocatalytic Dehydrogenation of Diaryl Hydrazines.

Direct utilization of solar energy by semiconductor nanocrystals for chemical transformations via photocatalysis has recently drawn a great deal of attention. While most photocatalytic reactions are mediated through photoredox events, the ultimate reaction scalability relies on the use of sacrificial agents. The imbalanced population of photogenerated electrons and holes often leads to catalyst degradation through photocorrosion. To circumvent this, we designed Ni2+-doped CsPbBr3 nanoplatelets (NPls) as a "redox-neutral" photocatalyst, where both oxidative and reductive cycles occur in one photocatalyst. We showed that surface Ni2+ ions can act as an "electron shuttle" to reduce protons, generating clean-energy H2 gas, while the photogenerated holes can be used to oxidize diaryl hydrazines to afford valuable azobenzenes and derivatives. Compared with previous photocatalytic demonstrations, our catalysts show excellent reaction yields with a wide substrate scope, unity atomic efficiency, and enhanced stability and recyclability.

Electrochemical Looping Using Tungsten Oxide for Electrolytic Hydrogenations

Global R&D associated with the production and utilization of hydrogen has been increasing dramatically to support the global effort to reduce CO2 emissions. Hydrogen can be used as a source of fuel and electricity, and it is also used as a chemical reductant for a host of industrial processes. One of the widely used applications of hydrogen in chemical industries is for hydrogenation reactions like ammonia synthesis and biomass hydrogenation. However, providing hydrogen for these reactions is practically challenging due to the several issues related to the high cost of infrastructure for hydrogen storage and transportation as well as safety concerns. These challenges could be mitigated if the hydrogen equivalents (i.e, protons and electrons) needed for these reactions can be supplied from water without producing H2 gas. In this study, we introduce the concept of electrochemical looping hydrogenation, in which, instead of producing H2, a solid hydrogen-transfer mediator is used to activate hydrogen through water electrolysis and subsequently deliver it catalytically to a target molecule. Here, tungsten oxide (WO3) plays the role of the mediator due to its ability to reversibly uptake and donate hydrogen atoms. In this process, hydrogen is electrochemically inserted into WO3 to form tungsten oxide hydrogen bronze (HxWO3). The stored hydrogen is then used to drive a chemical hydrogenation reaction via hydrogen de-insertion from HxWO3 and reformation of WO3. For this study, hydrogenation of 4-hydroxy TEMPO (2,2,6,6-tetramethylpiperidine N-oxyl) to 4-hydroxy TEMPO-H was chosen as a model hydrogen acceptor. The results validate proof-of concept for our electrochemical looping system and permit systematic measurements exploring the interplay between interfacial transfer and intra-phase transport of electrons and protons.

Assessment of hydrogen adsorption in high specific surface geomaterials using low-field NMR - Implications for storage and field characterization

Natural and produced hydrogen will play a central role in decarbonizing the economy. High specific surface geomaterials can contribute H2 adsorption capacity, affecting both natural systems and storage strategies. Low-field Nuclear Magnetic Resonance NMR provides unique insights into H2 gas adsorption on nanoporous geomaterials. The cumulative NMR amplitude correlates linearly with the hydrogen mass; furthermore, measurements reveal two relaxations: a short-time relaxation for adsorbed H2 gas, and a long-time pressure-dependent relaxation for free H2 gas within pores. NMR measurements and complementary Grand Canonical Monte Carlo simulations show 2.5-to-4 times higher density in adsorbed H2 than bulk H2. The H2 adsorption capacity varies with mineral composition, but in all cases, it increases with specific surface area. Therefore, hydrogen physisorption in nanoporous geomaterials improves storability with respect to single-phase pure gas storage when high specific surface bentonites (at low pressure) or activated carbon (at all pressures) are the adsorbents. While synthetic adsorbents may exhibit higher H2 storage capacities, the low cost of high specific surface geomaterials, the reduced storage buoyancy, and safer controlled release make these natural adsorbents particularly attractive for large-scale storage applications. The insights gained with low-field NMR measurements in the laboratory are directly applicable to the interpretation of down-hole NMR characterization tools in the field.

Predicting CO2 and H2 Solubility in Pure Water and Various Aqueous Systems: Implication for CO2–EOR, Carbon Capture and Sequestration, Natural Hydrogen Production and Underground Hydrogen Storage

The growing energy demand and the need for climate mitigation strategies have spurred interest in the application of CO2–enhanced oil recovery (CO2–EOR) and carbon capture, utilization, and storage (CCUS). Furthermore, natural hydrogen (H2) production and underground hydrogen storage (UHS) in geological media have emerged as promising technologies for cleaner energy and achieving net–zero emissions. However, selecting a suitable geological storage medium is complex, as it depends on the physicochemical and petrophysical characteristics of the host rock. Solubility is a key factor affecting the above–mentioned processes, and it is critical to understand phase distribution and estimating trapping capacities. This paper conducts a succinct review of predictive techniques and present novel simple and non–iterative predictive models for swift and reliable prediction of solubility behaviors in CO2–brine and H2–brine systems under varying conditions of pressure, temperature, and salinity (T–P–m salts), which are crucial for many geological and energy–related applications. The proposed models predict CO2 solubility in CO2 + H2O and CO2 + brine systems containing mixed salts and various single salt systems (Na+, K+, Ca2+, Mg2+, Cl−, SO42−) under typical geological conditions (273.15–523.15 K, 0–71 MPa), as well as H2 solubility in H2 + H2O and H2 + brine systems containing NaCl (273.15–630 K, 0–101 MPa). The proposed models are validated against experimental data, with average absolute errors for CO2 solubility in pure water and brine ranging between 8.19 and 8.80% and for H2 solubility in pure water and brine between 4.03 and 9.91%, respectively. These results demonstrate that the models can accurately predict solubility over a wide range of conditions while remaining computationally efficient compared to traditional models. Importantly, the proposed models can reproduce abrupt variations in phase composition during phase transitions and account for the influence of different ions on CO2 solubility. The solubility models accurately capture the salting–out (SO) characteristics of CO2 and H2 gas in various types of salt systems which are consistent with previous studies. The simplified solubility models for CO2 and H2 presented in this study offer significant advantages over conventional approaches, including computational efficiency and accuracy across a wide range of geological conditions. The explicit, derivative–continuous nature of these models eliminates the need for iterative algorithms, making them suitable for integration into large–scale multiphase flow simulations. This work contributes to the field by offering reliable tools for modeling solubility in various subsurface energy and environmental–related applications, facilitating their application in energy transition strategies aimed at reducing carbon emissions.

Recent Advances in Perovskite Nanomaterials for Sensing Applications

Abstract Perovskite-structured materials have been extensively studied for sensing applications on account of their good thermal stability and 3-4 eV bandgap. They have been utilized to detect traces of O2, NO, CO, NO2, CO2, H2O, CH4, H2 and similar smaller gas molecules such as C2H5OH etc. In addition, other sensing applications are optical sensing, I-V fluctuations, strain sensors, electromechanical sensors, sensing of metal ions, etc. Perovskite-structured halides are reported for sensing of metal ions, toxic gases, Volatile Organic Compounds (VOCs), detection of fungicides, pesticides, explosives, cellular imaging, radiation detection and humidity and temperature sensing.

Fabrication of hydrogen gas sensor using sputtered palladium-copper composite on tapered optical fiber

Abstract In this study, we fabricated a hydrogen (H2) gas sensor based on tapered optical fiber using sputtering method. Also, as the first attempt, we explored how palladium (Pd) and palladium-copper (Pd-Cu) coatings, deposited using the sputtering method (RF and DC), affect tapered optical fibers as H2 gas sensors (ranging from 1 to 8% H2). It investigates changes in sensor output power, response and recovery times, and the influence of fiber tapering angle on output power. The investigation reveals that two main factors, including permeability and elasto-optic effect significantly impact the results. At H2 concentrations of 1 to 3%, permeability predominantly affects Pd sensors, yielding better output power changes and sensitivity than Pd-Cu tapered optical fiber sensors. Conversely, at higher H2 concentrations (4 to 8%), the dominant factors appear to be permeability as well as elasto-optic effect. These characteristics have a greater influence in the Pd-Cu layer at higher H2 concentration, resulting in smoother slope in response to H2. Due to higher permeability, Pd sensors reach saturation faster, while Pd-Cu sensors exhibit more linear changes with increasing H2 levels and do not saturate like Pd sensors very fast. Moreover, the study shows that a larger tapering angle can enhance the output power of Pd-Cu tapered optical fiber sensors.

Improved hydrogen detection in SnO2-based materials using CuxPd bimetallic catalyst

Hydrogen (H2) holds promise as a replacement for conventional fossil fuels in future energy systems. However, developing a rapid, highly sensitive, and cost-effective H₂ sensor remains a significant challenge. This study first uses a low-cost-oriented CuxPd binary alloy for SnO2 for H2 sensing, and the corresponding properties are evaluated comprehensively. The results of H2 sensitivity demonstrate that our bimetallic CuxPd significantly enhances the sensitivity of SnO2, which is attributed to the synergistic effect of CuxPd bimetallic catalysts Our CuxPd/SnO2 nanocomposite materials not only exhibit high response (401 @ 1000 ppm at 100 °C), rapid response/recovery time (1/12 s @ 1000 ppm at 100 °C) and still maintains good response (1.42) to 1 ppm H2 gas. The introduction of Cu effectively stabilizes Pd and creates more oxygen vacancies, which provides a more catalytic effect than monometallic Pd. Therefore, this work provides a scenario for low-cost catalysis of H2 detection.

Influence of Electrode Surface Area and Processing Time on Chemical Oxygen Demand (COD) and Total Suspended Solid (TSS) Reduction in Tofu Wastewater Using Electrocoagulation

Electrocoagulation is a wastewater treatment process that uses electrochemical working principles to remove contaminants in solutions or wastewater. Where at the anode (negative current) metal ions are released into solution, while at the cathode (positive current) an electrochemical reaction occurs, namely the release of H2 (hydrogen) gas. Factors that influence the electrocoagulation process include electrode type, current strength, electrode cross-sectional area, process time, voltage, stirring, distance between electrodes, and acidity level (pH). The objective of this research is to investigate the effect of the surface area of the electrode and processing time on the COD and TSS of tofu wastewater. In this research, tofu industry liquid waste was processed using the electrocoagulation method using fixed variables including, Fe-Fe type electrodes, 4 electrodes, acidity level at 4, tofu liquid waste temperature at 25 ̊ C, distance between electrodes 2 cm, electrode thickness 2 mm, test sample of 4 liters and current strength of 13 V. The changing variables used are electrode cross-sectional area (70 cm² and 60 cm²) and processing time (30, 45, 60, 75, 90 minutes). In this study, the best conditions for reducing COD and TSS levels were obtained with a cross-sectional area of ​​70 cm² and a process time of 60 minutes for reducing COD levels and 30 minutes for reducing TSS levels. With a reduction in COD levels of 690.66 mg/L and a reduction in TSS levels of 181.25 mg/L. The results of reducing COD levels do not meet the tofu industry wastewater quality standard of 300 mg/L, and the results of reducing TSS levels meet the tofu industry wastewater quality standard of 200 mg/L.

Review on progress in synthesis of CdS‐based composites and their potential applications

AbstractIn recent times, there has been a growing interest among materials communities in functional nanomaterials. This paper aims to explore the fundamental advancements in the role of Cadmium sulfide (CdS) in photoelectrochemical water splitting, CO2 conversion, photocatalytic H2 conversion, photovoltaic devices, and gas sensors. Additionally, we provide a summary of key points and propose avenues for advancing research on CdS‐based composites.