Experimental 3E analysis of a biomass gasification plant for off-grid electrification in rural Ghana.

Techno-Economic Analysis of a Hybrid Renewable Energy System (HRES) with Biogas-Powered Combined Heat and Power (CHP) and Photovoltaic (PV) Systems

Built-in Interface electric field microenvironment in covalent organic framework modified heterojunction guiding Electron transfer for effective photocatalytic CO2 reduction.

Abstract CO 2 hydrogenation is a significant way to reduce carbon emissions, but it is facing serious challenges in selectivity control. Herein, we report a sequential dual‐step surface modulation strategy comprising phosphorus (P) incorporation into CeO 2 supports followed by selective ascorbic acid (AA)‐mediated etching. This approach enables precise tuning of product selectivity while maintaining exceptional catalytic activity. The final Rh/CeO 2 ‐P‐AA catalyst exhibits a significant enhancement in the CO generation rate, reaching 1336.3 mol CO mol Rh −1 h −1 with nearly 100% CO selectivity, almost 1.9 times higher than that of Rh/CeO 2 ‐P (691.8 mol CO mol Rh −1 h −1 ) and 6.7 times higher than that of Rh/CeO 2 (199.9 mol CO mol Rh −1 h −1 ). The incorporation of P induces an elevation of the surface states of Rh species, contributing to lower adsorption capacity for CO, thus leading to the selectivity changes. More importantly, benefiting from the weak acidity and reducibility, AA can assist in the re‐movement of some of the phosphate radicals and the partial reduction of Ce 4+ , thereby providing more oxygen defects for activating CO 2 .

CO2 hydrogenation is a significant way to reduce carbon emissions, but it is facing serious challenges in selectivity control. Herein, we report a sequential dual-step surface modulation strategy comprising phosphorus (P) incorporation into CeO2 supports followed by selective ascorbic acid (AA)-mediated etching. This approach enables precise tuning of product selectivity while maintaining exceptional catalytic activity. The final Rh/CeO2-P-AA catalyst exhibits a significant enhancement in the CO generation rate, reaching 1336.3 molCO molRh -1 h-1 with nearly 100% CO selectivity, almost 1.9 times higher than that of Rh/CeO2-P (691.8 molCO molRh -1 h-1) and 6.7 times higher than that of Rh/CeO2 (199.9 molCO molRh -1 h-1). The incorporation of P induces an elevation of the surface states of Rh species, contributing to lower adsorption capacity for CO, thus leading to the selectivity changes. More importantly, benefiting from the weak acidity and reducibility, AA can assist in the re-movement of some of the phosphate radicals and the partial reduction of Ce4+, thereby providing more oxygen defects for activating CO2.

Abstract Precisely tailoring the electronic effect of catalytic sites remains a fundamental challenge in the field of artificial photosynthesis. Particularly, the strategies for regulating orbital and electronic state via the Jahn–Teller (J–T) effect at the atomic level for boosting CO 2 photoreduction remain rarely investigated. Herein, a rational mitigation strategy is demonstrated via a single‐atom modification in metal‒organic assemblies which enables precise control over the J–T effect and thereby regulates the electron density at the locally catalytic Fe sites. Through rational ligand design, a nanolayer ( 1 ) exhibiting mitigated J–T distortion and a nanoribbon ( 2 ) with pronounced J–T distortion are synthesized. Remarkably, the photocatalyst 1 achieves a more rapid CO production rate of 10.91 mmol g −1 h −1 under visible light, nearly double that of 2 (6.19 mmol g −1 h −1 ). A combination of experimental analyses, including single‐crystal X‐ray diffraction, XPS, magnetic susceptibility, and in situ DRIFTS, as well as DFT calculations, reveals that the mitigation of the J–T effect noticeably enhances the charge density at the Fe active sites, which boosts CO 2 adsorption and activation, and ultimately promotes CO generation. This work demonstrates the prominence of the J–T engineering photocatalysts and highlights the potential of regulating orbital and electronic degeneracies for boosting artificial photosynthesis.

This study evaluated the economic viability and resilience of anaerobic digestion (AD) systems on United States (U.S.) dairy, revealing substantial vulnerabilities to policy and market shocks. While optimal Renewable Natural Gas (RNG) systems demonstrated a 54.0% success probability and positive mean Net Present Value (NPV) ($392,000) under baseline volatility, their viability is catastrophically degraded by federal policy shocks, causing the success probability to plummet to 1.4%. Conversely, Combined Heat and Power (CHP) systems showed a lower baseline success rate (32.6%) and negative mean NPV ($−156,000) but exhibit more gradual vulnerability. These findings were derived from an integrated analytical framework combining deterministic optimization, Monte Carlo simulation, and a novel multidimensional resilience assessment. Deterministic analysis confirmed that revenue diversification is essential for viability, with optimal RNG and CHP configurations achieving breakeven at 655 and 1165 cows, respectively. Our novel Composite Resilience Index (CRI) revealed a counterintuitive finding: despite RNG’s superior baseline profitability, CHP systems achieve a higher overall resilience score (52.3 vs. 47.7) due to better stability and shock resistance. These results highlight the critical importance of incorporating uncertainty and resilience considerations beyond traditional NPV analysis for renewable energy investment decisions.

Abstract The electrochemical reduction of CO 2 to ethylene (C 2 H 4 ) offers a promising approach to mitigating greenhouse gas emissions while generating high‐value chemical products. However, achieving both high C 2 H 4 selectivity and long‐term catalyst stability remains a significant challenge for single‐atom catalysts, primarily due to the absence of adjacent active sites required for the coupling of reaction intermediates. Herein, a bimetallic metal‐covalent organic framework (MCOF) with precisely tunable Cu‐Ag spatial configurations was developed to enhance CO 2 ‐to‐C 2 H 4 conversion through a synergistic catalytic mechanism. By optimizing the Cu/Ag molar ratio to 1:1 (Ag 0.5 Cu 0.5 ‐CTC‐TAPT), the catalyst achieves a Faradaic efficiency for C 2 H 4 (FE(C 2 H 4 )) of 51.5% ± 0.9% at a reduction potential of ‐1.774 V versus (vs.) RHE, along with a current density of 439.0 ± 7.3 mA cm −2 and excellent stability (FE(C 2 H 4 ) > 40% over 10 h), outperforming most single‐metal M/COFs and MOF‐based electrocatalysts that predominantly yield C1 products. In situ spectroscopic analysis and mechanistic studies indicate that Ag sites primarily facilitate CO generation, while neighboring Cu sites promote C─C bond formation. This work introduces a novel design strategy for constructing COF‐based materials with adjacent heterogeneous metal active sites, highlighting their significant potential for the electrochemical conversion of CO 2 into valuable C2+ chemicals.

The electrochemical reduction of CO2 to ethylene (C2H4) offers a promising approach to mitigating greenhouse gas emissions while generating high-value chemical products. However, achieving both high C2H4 selectivity and long-term catalyst stability remains a significant challenge for single-atom catalysts, primarily due to the absence of adjacent active sites required for the coupling of reaction intermediates. Herein, a bimetallic metal-covalent organic framework (MCOF) with precisely tunable Cu-Ag spatial configurations was developed to enhance CO2-to-C2H4 conversion through a synergistic catalytic mechanism. By optimizing the Cu/Ag molar ratio to 1:1 (Ag0.5Cu0.5-CTC-TAPT), the catalyst achieves a Faradaic efficiency for C2H4 (FE(C2H4)) of 51.5%±0.9% at a reduction potential of -1.774V versus (vs.)RHE, along with a current density of 439.0±7.3mA cm-2 and excellent stability (FE(C2H4)>40% over 10 h), outperforming most single-metal M/COFs and MOF-based electrocatalysts that predominantly yield C1 products. In situ spectroscopic analysis and mechanistic studies indicate that Ag sites primarily facilitate CO generation, while neighboring Cu sites promote C─C bond formation. This work introduces a novel design strategy for constructing COF-based materials with adjacent heterogeneous metal active sites, highlighting their significant potential for the electrochemical conversion of CO2 into valuable C2+ chemicals.

Solid Oxide Fuel Cells (SOFCs) are highly efficient energy conversion devices that produce electricity and heat through an electrochemical process. The widespread adoption of SOFCs is essential for achieving a sustainable, low-carbon society. Since 2012, OSAKA GAS has commercialized the ENE-FARM type S (EF) as a residential SOFCs combined heat and power (CHP) system. The widespread adoption of the EF requires addressing key challenges such as high efficiency, durability, low cost, and downsizing. EF was remodeled in 2016 and 2020 to address these issues. Metal-supported SOFCs (MSC) use a metal substrate that is low-cost and durable as a support, allowing for cost reduction and downsizing. However, there are concerns about the durability of the ferritic stainless-steel component at high temperatures. For this reason, MSC is generally positioned for low-temperature operation. Conversely, SOFCs constructed from ceramics are known to perform optimally at higher temperatures. Therefore, we have been working on the development of MSC that can be operated in the same temperature range as their anode-supported counterparts. The concepts of the MSC are to achieve both high output and high durability. In this study, the durability of MSC was evaluated at high temperature.The MSC was fabricated with ceramic electrodes and an electrolyte on a ferritic stainless-steel support with through-holes at low temperature. The configuration included a metallic interconnector, which was coated with ferritic stainless-steel welded around the cell, referred to as a Single Cell Unit (SCU). The perimeter welding between the cell and the metal interconnector served as a seal on the fuel side, ensuring gas tightness. The operating conditions involved a current density of 0.336 A/cm² and a mixed gas of H₂, N₂, and H₂O with Fuel Utilization (Uf) 80% supplied as fuel gas, along with air at Air Utilization (Ua) 30%. Durability evaluations were conducted in the temperature range of 700 to 850°C.Figure 1 shows the result of the durability testing at 700°C. Over the operation time of 10000 hours, the degradation of MSC-SCU was minimal. During the durability testing, the open circuit voltage (OCV) and internal resistance (IR), as well as electrode overvoltage (η), were measured. IR and η were measured using current interruption. The OCV of MSC-SCU showed almost no change during the 10000 hours durability testing. The small voltage degradation was attributed to increases in IR and η. It was assumed that potential causes for the increase in IR include reduced ionic conductivity due to phase transitions in the electrolyte, the formation of high-resistance layers, and increased oxide layer thickness. Factors contributing to the increase in η were related to sintering or poisoning of the fuel or air electrodes, leading to a decrease in the reaction area or reduced gas diffusion capability. In addition to separating IR and η, the influence on the fuel electrode side was evaluated by varying Uf. Uf dependence of the cell voltage changed little before and after durability testing. This result suggested that the factors contributing to the increase in η were likely located on the air electrode side rather than the fuel electrode side.The MSC is being developed for achieving compactness, lightweight design, and low cost, while striving to balance high efficiency and durability. In this study, the durability of the MSC under conditions of 700°C was evaluated. There was no rapid or significant degradation even after 10000 hours of operation at 700°C. To further enhance durability, we will continue to focus on improvements and long-term durability testing, with the goal of integrating these cells into the EF. Additionally, we are also exploring the technological application of SOEC to realize a decarbonized society. Figure 1

This article investigates a wind–solar–biogas complementary integrated energy system (IES) for achieving combined cooling, heating, and power (CCHP) supply in agricultural parks. The system consists of wind power, photovoltaic power, biogas-based combined heat and power (CHP), waste heat boilers, electric heating/cooling units, absorption chillers, and energy storage devices. Using Changma Village, Baiwu Town, Yanyuan County, Sichuan Province as a case study, a multi-objective optimization model was established with the objectives of minimizing operating costs and carbon emissions. An improved multi-objective grey wolf optimizer (MOGWO) was applied to solve the model. The results show that the proposed method yielded a well-distributed Pareto front. In the optimal compromise solution, the total operating cost decreased from CNY 6461.77 to CNY 2070.51, a reduction of 67.96%, and the carbon emissions decreased from 13,740.72 kg to 2370.45 kg, a reduction of 82.75%. The proposed wind–solar–biogas complementary IES can enhance both the overall economic performance and low-carbon sustainability of the agricultural park energy systems.

There has been significant progress in the electrochemical reduction of CO2 since the seminal work of Hori et al. in 1985 demonstrating hydrocarbon production at copper cathodes. The introduction of gas diffusion electrode (GDE) and membrane electrode assembly (MEA) flow cells have demonstrated progress to produce C2 products (ethylene, ethanol and acetate) at current densities >150 mA cm-2 with Faradaic Efficiencies (FE) >50% at different types of Cu cathodes. Selectivity depends on several pathways and the intermediate binding strength of species like *CO, *CHO, *OCCO, and *OCCOH. Thus, there are opportunities to engineer or optimize product selectivity.The work advanced ethylene production through Cu-P0.065 electrocatalyst (Cuδ+ = 0.13), achieving 52% FE at 150 mA cm-2 in 0.1 M KHCO3, and remarkably improving to 70% FE in weakly acidic conditions (pH 6) while maintaining 64% FE at 250 mA cm−2. Electrolyte engineering demonstrated that larger alkali cations (Na+ to Cs+) effectively suppress hydrogen evolution from 31% to 4% while promoting C2 formation (45% to 89% FE). K+ concentration optimization (0.1-2M) further enhanced ethylene production, increasing FE from 42% to 65% at 4V while reducing HER from 48% to 20%. Mechanistic studies revealed K+ and OH- species accumulation near the electrocatalyst surface promotes C-C coupling through K+ and *OCCO intermediate interactions, while phosphorus doping enhances *CO generation and coupling.In terms of ethanol our work demonstrates that Cu-Sn0.03 electrocatalyst (Cuδ+ = 0.27) can achieve 48% FE at 350 mA cm-2 under alkaline conditions. A breakthrough in product separation was achieved through a dual-layer membrane configuration incorporating CEM and AEM. This system, using 1M KOH (pH 14) inner layer and 1M KOH+H3PO4 (pH 6) anolyte, reached 51.92% FE for ethanol with minimal anode crossover (<1.07% FE), enabling direct production of >8 wt% ethanol. Additionally, anion identity studies (PO4 2-, SO4 2-, and NO4 -) demonstrated consistent C2 efficiencies (61-65%) at fixed pH.In terms of acetate production, we show Cu2Se electrocatalyst (Cuδ+ = 0.47), demonstrating 40% FE for acetate at 350 mA cm-2. Notably, all electrocatalysts maintained exceptional stability over 250 hours with minimal degradation (0.02% FE loss/hour). These results show structure-function relationships of electrocatalysts in CO2 reduction and high levels of ethylene, ethanol, and acetate production; however, several critical barriers related to operating (viz. Energy) cost and durability remain. We conclude with a review of the state of the art and the needs for commercialization.

Tandem electrocatalysis, also referred to as sequential or cascade electrocatalysis, is a process in which multiple catalytic steps take place consecutively at distinct active sites within the same system. Inspired by enzymatic processes, this approach relies on the intermediate formed at one catalytic site serving as a reactant for the subsequent stage. By carefully integrating electrocatalysts and co-catalysts, tandem systems enhance reaction efficiency through synergistic effects, lower energy barriers, and improve selectivity toward targeted products.This study presents four case studies developed in our laboratory, focusing on the electrochemical reduction of CO₂ and N₂. Both transformations are pivotal for the energy transition, as they provide alternative electrochemical routes for carbon dioxide capture and conversion into valuable compounds while also promoting more sustainable methods for ammonia synthesis, moving away from the conventional Haber-Bosch process.In the first example, copper nanocubes are synthesized on copper electrodes and subsequently doped with silver nanoparticles via a galvanic displacement reaction. Analysis using Raman spectro-electrochemistry (Raman-SEC), electrochemical impedance spectroscopy (EIS), and differential electrochemical mass spectrometry (DEMS) reveals that at approximately -0.8 V vs. RHE, the reaction mechanism favors maximum CO generation before shifting selectivity toward ethylene formation. The second system involves copper nanocube electrodes doped with Zn nanoparticles, electrodeposited from ethaline. Electrolysis, combined with Raman-SEC, EIS, and DEMS studies, indicates that the density of active Zn sites plays a key role in directing the reaction pathway toward ethylene production. Additionally, the integration of Cu₂O nanocubes with Bi microparticles—electrodeposited through a pulsed potential protocol using ethaline as a solvent—enables selective methanol production at -0.2 V vs. RHE, achieving a faradaic efficiency of 70%.For the electrochemical reduction of N₂, a composite material composed of MoS₂ doped with FeS₂ was employed as the electrocatalyst. When FeS₂ doping reached 10%, a maximum faradaic efficiency of 13% for ammonia formation was observed, demonstrating a pronounced synergistic effect. In all cases, experiments were designed to provide empirical evidence supporting the selective generation of key intermediates, confirming the cascade reaction mechanism. Acknowledgments This research was supported by FONDECYT Regular Project 1221179, the Millennium Institute of Green Ammonia as an Energy Vector (ICN2021_023, MIGA), and the ANID National PhD Scholarship 21221294.

Within the Micro-Bio-CHP project, funded under the Horizon Europe program, an energy supply system for energy autonomous multi-family buildings based on biomass gasification coupled with a SOFC system shall be implemented. In contrast to conventional CHP-solutions, a partial flow of the product gas is extracted from the biomass gasifier and led to the SOFC system for highly efficient electricity production. BIOS Bioenergiesysteme GmbH as the consortium lead operates the CHP plant with its experience in biomass gasification.The aim of the project is to achieve a high fuel utilization of over 75 % and high electric efficiencies on stack level of more than 44 %. Therefore, a stack module from Fraunhofer IKTS with 3x40 cell stacks was integrated into a SOFC system from INERGIO Technology SA, also containing a HCl- and H2S-removal unit from Hysytech S.r.l. The first operation of the coupled systems shows promising results. The targeted quality of the gas was reached and can be converted by SOFC with an electric efficiency at stack level of 45%. An environmental and overall impact assessments will be performed by the institute WIKUE.Although a highly efficient thermal and catalytic tar reforming is achieved through a catalyst developed by Catator AB, a residual benzene fraction can be found in the product gas. Therefore, contamination tests with benzene were conducted on a single stack to evaluate the influence on the performance on a scientific level.

Photocatalytic reduction of carbon dioxide is a clean and sustainable method for carbon emission reduction. However, most of the reported photocatalysts for CO2 reduction can produce only CO and CH4. Phosphorus with the bandgap of 1.6 eV is a promising photocatalyst, but the slow C-C coupling efficiency renders pure phosphorus to fail to produce C2 products. Herein, we found that the iron-modified Red P photocatalyst can reduce CO2 to C2H4 and C2H6. The yield of C2H4 (32.47 μmol·g-1·h-1) is much higher than that of CO (2.04 μmol·g-1·h-1), CH4 (2.36 μmol·g-1·h-1). Moreover, when PdFe substitutes for Fe, no C2H6 is produced, the generation of C2H4 further increases, while CO and CH4 are suppressed, with their yields decreasing by about 72.8 and 17.5 times, respectively. The yield of C2H4 increases to 44.91 μmol·g-1·h-1, and its selectivity of C2H4 increases to 99.79%, which is the highest value among state-of-the-art photocatalysts. The C-C coupling can be achieved through a "channel" between Fe atoms in the Fe-P system. This study proposes a catalyst for reducing carbon dioxide to ethylene and broadens people's understanding and application of photocatalysts.

The development of application-oriented, highly active, and selective CO2 reduction reaction (CO2RR) electrocatalysts for high value-added products is expected to achieve carbon neutrality and solve the problem of energy shortage. Cu-based catalysts, as the most promising catalysts for high value-added product generation, were often limited by slow CO generation and weak CO adsorption in practical applications. Guided by theoretical screening, herein, an atomic-scale CuZn alloy cluster configuration was manipulated on covalent organic frameworks (COFs), and its CO2RR performance was further improved by the regulation of the electron-donor functional groups. Through systematic characterization and theoretical simulations, we for the first time demonstrate and quantify the interstitial electrons in CuZn alloy clusters under the regulation of electron-giving groups. Further in situ surface-enhanced Raman spectroscopy (SERS) and simulation results reveal that the behavior of interstitial electrons with low work function and high mobility occupy the high-energy orbital of the metal and easily transfer to *CO, therefore, the *CO is hydrogenated to *COH before coupling, and then the coupling energy barrier and path are optimized. Due to these attributes, the as-developed CuZn alloy-functionalized COF catalyst (CuZn-COF-OH) exhibits significantly improved activity and selectivity, with >200mA cm-2 industrial-grade current density and ethylene Faraday efficiency of up to ∼79% at-1.0V versus RHE. This study provides innovative avenues and insights for the design and development of application-oriented atomic-scale catalysts.

This paper presents an advanced operational framework for large-scale combined heat and power (CHP)-based multi-carrier energy (MCE) networks integrating both electrical and gas energy storage systems (EESS and GESS). A novel coordinated controller is developed to regulate energy flows by managing charging and discharging cycles of storage units while stabilizing electricity and gas supply to CHP units. The operational optimization problem is solved using a parameter-free Teaching-Learning-Based Optimization (TLBO) algorithm, which efficiently minimizes total costs and enhances system flexibility. The proposed approach is validated on a comprehensive testbed comprising the IEEE 14-bus power system, the Belgian natural gas network, and district heating subsystems. Results showed that the presence of EESS reduced the total operation cost of the network by about 0.075%, while the use of GESS increased the operation cost by about 0.024%. Overall, the framework significantly improves operational cost efficiency, energy flow stability, and network resilience compared to existing methods. This work provides valuable insights into the integration and coordinated control of multi-energy storage in CHP-based MCE networks, contributing to the development of more sustainable and flexible energy systems.

Abstract The electrochemical carbon dioxide reduction reaction (CO 2 RR) represents a promising strategy for converting CO 2 into CO. Atomically dispersed transition metal sites have an exceptional ability to activate CO 2 . However, the strong hybridization between the 3 d orbitals of these transition metals and the 5σ or 2π * orbital of CO significantly impedes * CO desorption, thereby limiting the overall CO generation activity. In contrast, s ‐block metals, with diffuse 3 s electron clouds, exhibit weaker interactions with * CO. Nevertheless, their practical application is hindered by the high energy barrier associated with the formation of the * COOH intermediate. To address these challenges, a fluorine(F)‐tuned magnesium single‐atom catalyst (Mg‐SAC) is developed. Remarkably, this catalyst achieved a CO Faraday efficiency of 97.3% and a current density of 260.4 mA cm −2 at −0.4 V vs the reversible hydrogen electrode in a flow cell, surpassing the performance of most state‐of‐the‐art SACs and transition metal catalysts reported in the literature. Mechanistic studies reveal that * CO desorption on Mg sites is significantly easier compared to that on Fe and Co sites. Furthermore, the incorporation of F atoms modifies the electronic structure of the MgN 4 sites, substantially lowering the energy barrier for the formation of the critical * COOH intermediate.

The accelerating deterioration of the global environment underscores the urgent need to transition from the conventional fossil fuels to renewable energy, particularly the abundant solar energy. However, large-scale solar power integration could cause the severe grid fluctuations and compromise the operational stability. Existing studies have attempted to address this issue using hydrogen-based energy storage for peak shaving, but most suffer from low system efficiency. To overcome these limitations, this study proposes a novel solar-driven integrated energy system (IES) for hydrogen production and combined heat and power (CHP) generation, in which advanced hydrogen storage technologies are employed to achieve the efficient system operation. The system couples four subsystems: parabolic trough solar collector (PTSC), transcritical CO2 power cycle (TCPC), Kalina cycle (KC) and proton exchange membrane electrolytic cell (PEMEC). Thermodynamic analysis of the proposed IES was conducted, and the effects of key parameters on system performance were investigated in depth. Simulation results show that under design conditions, the PEMEC produces 0.514 kg/h of hydrogen with an energy efficiency of 54.09% and an exergy efficiency of 51.59%, respectively. When the TCPC evaporator outlet temperature is 430.35 K, the IES achieves maximum energy and exergy efficiencies of 46.52% and 18.62%, respectively, with a hydrogen production rate of 0.51 kg/h. The findings highlight the importance of coordinated parameter optimization to maximize system efficiency and hydrogen productivity, providing theoretical guidance for practical design and operation of solar-based hydrogen integrated energy system.

Abstract Highly selective photoconversion of CO 2 into value‐added fuels is crucial yet still restricted by efficacious catalysts with established structure‐activity correlations. Herein, through a linker rigidity‐flexibility modulation strategy utilizing rigid pyrene or relatively flexible biphenyl as parts of motifs, two covalent organic frameworks (COFs) with topological divergence bearing Ni single atoms are obtained for efficient CO 2 photoreduction. Pyrene‐containing Ni‐BPYP‐COF with hit topology manifests an impressive CO generation rate of 21.1 mmol g −1 h −1 , outperforming biphenyl‐incorporating Ni‐BPYA‐COF with bex topology by 2.5‐fold. Notably, even under simulated flue gas conditions (15% CO 2 ), Ni‐BPYP‐COF maintains outstanding activity, yielding CO at 15.4 mmol g −1 h −1 (≈100% selectivity). Extensive experimental and theoretical studies reveal that, despite the comparable NiN 2 O 4 catalytic sites, the greater conjugation and irregular hexagonal tessellation of the Ni‐BPYP‐COF enhance its ability to harvest visible light, augment dipole moments that are beneficial for charge separation, and allow for precise tuning of the d ‐band center position, facilitating CO 2 activation and the generation of * CO intermediates. The findings underscore the synergistic interaction between linker‐governed conjugation and topology in modulating the electronic structure of COFs, thereby improving CO 2 photoreduction activity and providing insights for developing selective photocatalysts.