Conversion Efficiency Research Articles

Interface-modulated kinetic differentials in electron and hole transfer rates as a key design principle for redox photocatalysis by Sb2VO5/QD heterostructures.

The efficient conversion of solar energy to chemical energy represents a critical bottleneck to the energy transition. Photocatalytic splitting of water to generate solar fuels is a promising solution. Semiconductor quantum dots (QDs) are prime candidates for light-harvesting components of photocatalytic heterostructures, given their size-dependent photophysical properties and band-edge energies. A promising series of heterostructured photocatalysts interface QDs with transition-metal oxides which embed midgap electronic states derived from the stereochemically active electron lone pairs of p-block cations. Here, we examine the thermodynamic driving forces and dynamics of charge separation in Sb2VO5/CdSe QD heterostructures, wherein a high density of Sb 5s2-derived midgap states are prospective acceptors for photogenerated holes. Hard-x-ray valence band photoemission spectroscopy measurements of Sb2VO5/CdSe QD heterostructures were used to deduce thermodynamic driving forces for charge separation. Interfacial charge transfer dynamics in the heterostructures were examined as a function of the mode of interfacial connectivity, contrasting heterostructures with direct interfaces assembled by successive ion layer adsorption and reaction (SILAR) and interfaces comprising molecular bridges assembled by linker-assisted assembly (LAA). Transient absorption spectroscopy measurements indicate ultrafast (<2ps) electron and hole transfer in SILAR-derived heterostructures, whereas LAA-derived heterostructures show orders of magnitude differentials in the kinetics of hole (<100ps) and electron (∼1ns) transfer. The interface-modulated kinetic differentials in electron and hole transfer rates underpin the more effective charge separation, reduced charge recombination, and greater photocatalytic efficiency observed for the LAA-derived Sb2VO5/CdSe QD heterostructures.

Soldering Pressure Effect on Lifetime of Thermoelectric Modules under Thermal Cycling.

For practical industrial applications, enhancing the longevity and the reliability of thermoelectric modules (TEMs) is equally as crucial as improving their conversion efficiency. This study proposes a strategy for extending the lifespan and introduces the quality evaluation criteria for the most extensively used commercial bismuth telluride TEM. By varying the soldering pressure during module assembly, its impact on the quality of the module's internal interfacial connections was investigated, via analyzing its contact resistivity, shear modulus, and antifatigue ability through thermal cycling tests. The findings reveal that increasing the soldering pressure leads to a slight reduction in interfacial contact resistivity and has no significant effect on the shear modulus but notably enhances the module's antifatigue ability during thermal cycling tests. According to the SEM results, it can be evidently deduced that the aforementioned phenomena are directly correlated with the size and quantity of voids distributed in the solder layer, which is regarded as the origin of antifatigue ability. Thus, it can be inferred that augmenting the soldering pressure represents an effective approach to prolonging the lifespan of TEMs assembled by using the soldering method. Furthermore, the existence of voids within the solder layer can serve as a criterion for an initial assessment of module longevity. This study provides a reference for both the industrial assembly and lifespan evaluation of commercial bismuth telluride TEMs.

Surface-Enriched Room-Temperature Liquid Bismuth for Catalytic CO2 Reduction.

Bismuth-based electrocatalysts are effective for carbon dioxide (CO2) reduction to formate. However, at room temperature, these materials are only available in solid state, which inevitably suffers from surface deactivation, declining current densities, and Faradaic efficiencies. Here, the formation of a liquid bismuth catalyst on the liquid gallium surface at ambient conditions is shown as its exceptional performance in the electrochemical reduction of CO2 (i.e., CO2RR). By doping a trace amount of bismuth (740ppm atomic) in gallium liquid metal, a surface enrichment of bismuth by over 400 times (30 at%) in liquid state is obtained without atomic aggregation, achieving 98% Faradic efficiency for CO2 conversion to formate over 80 h. Ab initio molecular simulations and density functional theory calculations reveal that bismuth atoms in the liquid state are the most energetically favorable sites for the CO2RR intermediates, superior to solid Bi-sites, as well as joint GaBi-sites. This study opens an avenue for fabricating high-performing liquid-state metallic catalysts that cannot be reached by elementary metals under electrocatalytic conditions.

One-Stone-for-Two-Birds Method to Improve the SnO2 Layers for High Power-per-Weight Flexible Perovskite Solar Cell Mini-modules.

Maintaining the power conversion efficiency (PCE) of flexible perovskite solar cells (fPSCs) while decreasing their weight is essential to utilize their lightweight and flexibility as much as possible for commercialization. Strengthening the interfaces between functional layers, such as flexible substrates, charge transport layers, and perovskite active layers, is critical to addressing the issue. Herein, we propose a feasible and one-stone-for-two-birds method to improve the electron transport layer (ETL), SnO2, and the interface between the ETL and perovskite layer simultaneously. In detail, poly(acrylate ammonium) (PAAm), a low-cost polymer with a long chain structure, is added into the SnO2 aqueous solution to reduce the aggregation of SnO2 nanoparticles, resulting in the deposition of a conformal and high-quality ETL film on the tin-doped indium oxide film surface. Simultaneously, PAAm addition can effectively regulate the crystallization of the perovskite films, strengthening the interface between the SnO2 film and the buried surface of the perovskite layer. The outstanding PCEs of 22.41% on small-scale fPSCs and 18.54% on fPSC mini-modules are among the state-of-the-art n-i-p type fPSCs. Moreover, the fPSC mini-module on the 20 μm-thick flexible substrate shows a comparable PCE with that of the fPSC mini-module on the 125 μm-thick flexible substrate, exhibiting a high power-to-weight of 5.097 W/g. This work provides an easy but essential direction for further applications of fPSCs in diverse scenarios.

Enhancing dye-sensitized solar cell performance: Optimizing Cu2ZnSnS4/ZnCo2O4 nanocomposites as efficient and cost-effective counter electrodes

This study investigates the utilization of Cu2ZnSnS4/ZnCo2O4 (CZTS/ZCO) nanocomposites prepared through hydrothermal and combustion methods as counter electrodes in Dye-Sensitized Solar Cells (DSSCs). Different ratios of Cu2ZnSnS4 and ZnCo2O4 were explored, and comprehensive analyses were conducted using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), High-Resolution TEM (HRTEM), Brunauer–Emmett–Teller (BET) surface area analysis, Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), cyclic voltammetry (CV), Tafel analysis, Field Emission Scanning Electron Microscopy (FESEM), and Incident Photon-to-Electron Conversion Efficiency (IPCE), alongside long-term stability assessments. The CZTS:ZCO ratio of 2:1 exhibited the highest efficiency, reaching 8.81 %, with an open-circuit voltage of 729 mV, short-circuit current of 17.80 mAcm−2, and a fill factor of 67.9 %. This surpasses the efficiency of the reference Pt cell (8.42 %), which had an open-circuit voltage of 735 mV, short-circuit current of 17.16 mAcm−2, and a fill factor of 66.8 %. The average crystallite sizes for the main peaks of CZTS and ZCO samples were estimated to be 19.8 and 16.7 nm, respectively. The crystallite size can significantly affect the charge transfer and conductivity in the counter electrode during electrochemical processes; the presence of nanocrystals with these sizes can notably enhance the electrochemical properties and conductivity of the synthesized samples. Raman analysis results indicate that no additional phases or secondary phases such as ZnS and CuSnS3 have formed in the kesterite CZTS structure, and the crystal has formed as a single phase. Additionally, the F2g modes in the Raman spectrum of ZCO indicate tetrahedral units in the spinel ZCO structure, and the A1g modes represent octahedral structures in this phase, indicating the formation of suitable ZCO phase. The superior performance of the CZTS/ZCO nanocomposite can be attributed to its enhanced crystalline structure, superior charge transport characteristics, and improved electrocatalytic behaviours.

Experimental design and analysis of advanced three phase converter for PV application with WCO-P&O MPPT controller

Photovoltaic (PV)-based power generation systems are becoming increasingly popular as a due to its high performance and cleanliness. Several factors influence the performance of a PV system, including shadowing effects. PV systems employ MPPT methodologies to obtain the power from PV array. Conventional MPPTs works well under normal conditions when there is no shadow effects or partial shading. The presence of partial shading affects the system performance and generates several power peaks. This complicates the process of finding out of the global peak (GMPP) with improved tracking efficiency and reduced settling time including conversion efficiency. This work proposes three hybrid MPPT techniques: Water Cycle Optimisation-Perturb and Observe (WCO-PO), Artificial Neural Network Supported Adaptable Stepped-Scaled Perturb and Observe (ANN-ASSPO), Grey Wolf Optimisation-Modified Fast Terminal Sliding Mode Controller (GWO-MFTSMC), and two conventional MPPT techniques WCO and P&O have been implemented. The proposed system utilizes interleaved boost converter with three phase. The performances of proposed hybrid MPPTs strategies were compared in terms of output voltage, output current and extracted power. The comparison also includes conversion efficiency and average settling time. To analyse the performances, four different cases have been used to test the efficacy of hybrid MPPTs under changing climatic conditions. The MATLAB/Simulink tool has been used to analyze the PV system performances. In the three hybrid MPPT techniques, WCO-PO has performed better when compared to other two hybrid MPPTs in terms of conversion efficiency (99.56%) and settling time (1.4 m).

Biomass source influence on hydrogen production through pyrolysis and in line oxidative steam reforming.

This study evaluates the potential of several biomasses differing in nature and composition for their valorization by pyrolysis and in-line oxidative steam reforming. The first task involved the fast pyrolysis of the biomasses in a conical spouted bed reactor at 500ºC, in which product yields were analyzed in detail. Then, the oxidative steam reforming of pyrolysis volatiles (gases and bio-oil) was approached in a fluidized bed reactor. The reforming experiments were performed at 600 ºC, with an steam/biomass (S/B) ratio of 3 and catalyst (Ni/Al2O3) space times of 7.5 and 20 gcat min gvol-1. Concerning equivalence ratio (ER), a value of 0.12 was selected to ensure autothermal operation. Remarkable differences were observed in H2 production depending on the type of biomass. Thus, pine wood led to a H2 production of 9.3 wt%. The lower productions obtained with rice husk (7.7 wt%) and orange peel (5.5 wt%) are associated with their higher ash and fixed carbon content, respectively, which limit the efficiency of biomass conversion to bio-oil. However, in the case of the microalga, the poor performance observed is due to the lower conversion in the reforming step toward gases due to the composition of its pyrolysis volatile stream.

Defect-enabling zirconium-based metal-organic frameworks for energy and environmental remediation applications.

This comprehensive review explores the diverse applications of defective zirconium-based metal-organic frameworks (Zr-MOFs) in energy and environmental remediation. Zr-MOFs have gained significant attention due to their unique properties, and deliberate introduction of defects further enhances their functionality. The review encompasses several areas where defective Zr-MOFs exhibit promise, including environmental remediation, detoxification of chemical warfare agents, photocatalytic energy conversions, and electrochemical applications. Defects play a pivotal role by creating open sites within the framework, facilitating effective adsorption and remediation of pollutants. They also contribute to the catalytic activity of Zr-MOFs, enabling efficient energy conversion processes such as hydrogen production and CO2 reduction. The review underscores the importance of defect manipulation, including control over their distribution and type, to optimize the performance of Zr-MOFs. Through tailored defect engineering and precise selection of functional groups, researchers can enhance the selectivity and efficiency of Zr-MOFs for specific applications. Additionally, pore size manipulation influences the adsorption capacity and transport properties of Zr-MOFs, further expanding their potential in environmental remediation and energy conversion. Defective Zr-MOFs exhibit remarkable stability and synthetic versatility, making them suitable for diverse environmental conditions and allowing for the introduction of missing linkers, cluster defects, or post-synthetic modifications to precisely tailor their properties. Overall, this review highlights the promising prospects of defective Zr-MOFs in addressing energy and environmental challenges, positioning them as versatile tools for sustainable solutions and paving the way for advancements in various sectors toward a cleaner and more sustainable future.

Hierarchical porous carbon materials for lithium storage: Preparation, modification, and applications.

Secondary battery as an efficient energy conversion device have been highly attractive for alleviating the energy crisis and environmental pollution. Hierarchical porous carbon materials with multiple sizes pore channels are considered as promising materials for energy conversion and storage applications, due to their high specific surface area and excellent electrical conductivity. Although many reviews have reported on carbon materials for different fields, systematic summaries about hierarchical porous carbon materials for lithium storage are still rare. In this review, we fist summarize the main preparation methods of hierarchical porous carbon materials, including hard template method, soft template method, and template-free method. The modification methods including porosity and morphology tuning, heteroatom doping, and multiphase composites are introduced systematically. Then, the recent advances in hierarchical porous carbon materials on lithium storage are summarized. Finally, we outline the challenges and future perspectives for the application of hierarchical porous carbon materials in lithium storage.

All-Inorganic Halide Perovskites Boost High-Ranged Figure-of-Merit in Bi0.4Sb1.6Te3 for Thermoelectric Cooling and Low-Grade Heat Recovery.

The all-inorganic halide perovskite CsPbX3 (X = Cl, Br, or I) offers various advantages, such as tunable electronic structure and high carrier mobility. However, its potential application in thermoelectric materials remains underexplored. In this study, we propose a simple yet effective method to synthesize a CsPbX3/Bi0.4Sb1.6Te3 (BST) nanocomposite by sintering a uniformly mixed raw powder. The intrinsic excitation of the BST system is suppressed by exploiting the rich phase structure and tunable electrical transport properties of CsPbX3, and the thermoelectric properties were synergistically optimized. Notably, for CsPbI3, its phase-transition-induced dislocation arrays together with low group velocities drastically reduce thermal conductivity. As a result, the composite achieves an ultrahigh average figure-of-merit (ZT) of 1.4 from 298 to 523 K. The two-pair TE module demonstrates a superior conversion efficiency of 7.3%. This study expands the potential applications of inorganic halide perovskites, into thermoelectrics.

Polydopamine Nanocarriers with Cascade-Activated Nitric Oxide Release Combined Photothermal Activity for the Therapy of Drug-Resistant Bacterial Infections.

Antibiotic abuse leads to increased bacterial resistance, and the surviving planktonic bacteria aggregate and secrete extracellular polymers to form biofilms. Conventional antibacterial agents find it difficult to penetrate the biofilm, remove the bacteria wrapped in it, and produce an excellent therapeutic effect. In this study, a dual pH- and NIR-responsive nanocomposite (A-Ca@PDA) was developed to remove drug-resistant bacteria through a cascade of catalytic nitric oxide (NO) release and photothermal clearance. NO can melt in the outer package of the biofilm, facilitating the nanocomposites to have better permeability. Thermal therapy further inhibits the growth of planktonic bacteria. The locally generated high temperature and the burst release of NO together aggravate the biofilm collapse and bacterial death after NIR irradiation. The nanocomposites achieved a remarkable photothermal conversion efficiency of 47.5%, thereby exhibiting significant advancements in energy conversion. The nanocomposites exhibited remarkable efficacy in inhibiting multidrug-resistant (MDR) Escherichia coli and MDR Staphylococcus aureus, thus achieving an inhibition rate of >90%. Moreover, these nanocomposites significantly improved the wound-healing process in the MDR S. aureus-infected mice. Thus, this novel nanocomposite offers a novel strategy to combat drug-resistant bacterial infections.

Counter-Doping Effect by Trivalent Cations in tin-based Perovskite Solar Cells.

Sn-based perovskite solar cells normally show low open circuit voltage due to serious carrier recombination in the devices, which can be attributed to the oxidation and the resultant high p-type doping of the perovskite active layers. Considering the grand challenge to completely prohibit the oxidation of Sn-based perovskites, a feasible way to improve the device performance is to counter-dope the oxidized Sn-based perovskites by replacing Sn2+ with trivalent cations in the crystal lattice, which however has been rarely reported. Here, we present the introduction of Sb3+, which can effectively counter-dope the oxidized perovskite layer and improve the carrier lifetime. Meanwhile, Sb3+ can passivate deep-level defects and improve carrier mobility of the perovskite layer, which are all favourable for the photovoltaic performance of the devices. Consequently, the target devices yield a relative enhancement of the power conversion efficiency (PCE) of 31.4% as well as excellent shelf-storage stability. This work provides a novel strategy to improve the performance of Sn-based perovskite solar cells, which can be developed as a universal way to compensate for the oxidation of Sn-based perovskites in optoelectronic devices. This article is protected by copyright. All rights reserved.

SnSe2 Quantum Dots and Chlorhexidine Acetate Suppress Synergistically Non-radiative Recombination Loss for High Efficiency and Stability Perovskite Solar Cells.

Non-radiative recombination losses limit the property of perovskite solar cells (PSCs). Here, a synergistic strategy of SnSe2QDs doping into SnO2 and chlorhexidine acetate (CA) coating on the surface of perovskite is proposed. The introduction of 2D SnSe2QDs reduces the oxygen vacancy defects and increases the carrier mobility of SnO2. The optimized SnO2 as a buried interface obviously improves the crystallization quality of perovskite. The CA containing abundant active sites of ─NH2/─NH─, ─C═N, CO, ─Cl groups passivate the defects on the surface and grain boundary of perovskite. The alkyl chain of CA also improves the hydrophobicity of perovskite. Moreover, the synergism of SnSe2QDs and CA releases the residual stress and regulates the energy level arrangement at the top and bottom interface of perovskite. Benefiting from these advantages, the bulk and interface non-radiative recombination loss is greatly suppressed and thereby increases the carrier transport and extraction in devices. As a result, the best power conversion efficiency (PCE) of 23.41% for rigid PSCs and the best PCE of 21.84% for flexible PSCs are reached. The rigid PSC maintains 89% of initial efficiency after storing nitrogen for 3100 h. The flexible PSCs retain 87% of the initial PCE after 5000 bending cycles at a bending radius of 5 mm.

Impact of La doping on the optoelectronic and structural properties of CsPbIBr2 perovskite solar cell

Inorganic lead halide perovskite solar cells (IPSC) have high power conversion efficiency (PCE). Currently, heteroatom substitution is a promising method for enhancing the properties of perovskite materials and the performance of associated devices. This study outlines the production process of a perovskite solar cell made from inorganic CsPbIBr2 with a 4 % La doping. The cubic crystal structure with large grain size and small band gap energy is observed at 4 % La–CsPbIBr2. The optoelectronic and structural characteristics of CsPbIBr2 perovskite solar cells have been substantiated through various methodologies, such as the determination of space charge restricted current, examination of the photoluminescence decay profile, assessment of charge transfer resistance, and utilization of Mott Schottky analysis. The incorporation of lanthanum-doped cesium lead iodide bromide (La-doped CsPbIBr2) resulted in a notable enhancement in both the open circuit voltage (Voc), and the short circuit current density (Jsc), leading to a much higher overall efficiency of 9.89 % compared to the pristine counterpart, which exhibited an efficiency of 8.62 %.

Low levels of chicken body louse (Menacanthus stramineus) infestations affect chicken welfare in a cage-free housing system

BackgroundThe chicken body louse is an obligate ectoparasite of domestic chickens. Chicken body lice feed on feathers, and infestation with this louse is linked to decreases in egg production, hen weight, and feed conversion efficiency. However, it is unknown how chicken body lice impact egg-laying chickens in cage-free environments. Welfare and behavior metrics were collected from flocks of egg-laying chickens either infested with chicken body lice or left uninfested.MethodsIn two trials, two flocks of cage-free commercial egg-laying chickens were infested with chicken body lice or maintained as uninfested controls. At three timepoints, behavior and welfare of all chickens was measured. On-animal sensors were used to quantify pecking, preening, and dustbathing behavior. Other animal-based welfare metrics included recording comb wounds and skin lesions.ResultsBirds infested with chicken body lice exhibited significantly more preening behaviors than uninfested birds, even at low louse levels. Moderate or severe skin lesions were detected on birds that were moderately infested with chicken body lice while skin lesions were never detected on uninfested birds.ConclusionsThe welfare of chickens was impacted by the chicken body louse, a chewing louse that primarily feather feeds. Evidence of skin lesions on infested birds suggests that lice may cause more damage to birds than previously thought, and further evaluation of louse economic damage is necessary.Graphical

Chlorinated Oligomers with Regulate Planarity Achieving Superior Photovoltaic Performance.

Chlorine substitution, as an effective and low-cost modification strategy, has been applied in the design of donor and acceptor structures in organic solar cells. We synthesized a series of chlorinated dimerized acceptors to investigate the effect of chlorine numbers and locations on the photovoltaic properties. The results show that the planarity and morphology of DYV-γ-2Cl are greatly improved due to the appropriate numbers and positions of the substituted chlorine atoms. Therefore, the device based on PM6:DYV-γ-2Cl achieves a superior power conversion efficiency (PCE) of 15.54% among the three oligomeric acceptors with optimized molecular planarity and film morphology. This work demonstrated the positive effect of suitable numbers and the substitution positions of chlorines on the molecular arrangement and photovoltaic properties of the corresponding dimerized acceptors.

Work Function Tuning of Carbon Electrode to Boost the Charge Extraction in Hole Transport Layer-Free Perovskite Solar Cells.

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF)of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

Active Passivation of Anion Vacancies in Antimony Selenide Film for Efficient Solar Cells.

Binary antimony selenide (Sb2Se3) is a promising inorganic light-harvesting material with high stability, non-toxicity and wide light harvesting capability. In this photovoltaic material, it has been recognized that deep energy level defects with large carrier capture cross section, such as VSe (selenium vacancy), lead to serious open-circuit voltage (VOC) deficit and in turn limit the achievable power conversion efficiency (PCE) of Sb2Se3 solar cells. Understanding the nature of deep-level defects and establishing effective method to eliminate the defects are vital to improving VOC. In this study, we propose a novel directed defect passivation strategy to suppress the formation of VSe and maintaining the composition and morphology of Sb2Se3 film. In particularly, through systematic study on the evolution of defect properties, we reveal the pathway of defect passivation reaction. Owing to the inhibition of defect-assisted recombination, the VOC increases, resulting in an improvement of PCE from 7.69% to 8.90%, where is the highest efficiency of Sb2Se3 solar cells prepared by thermal evaporation method with superstrate device configuration. This study proposes a new understanding of the nature of deep-level defects and enlightens the fabrication of high quality Sb2Se3 thin film for solar cell applications. This article is protected by copyright. All rights reserved.

Equally Efficient Perovskite Solar Cells and Modules Fabricated via N-Ethyl-2-Pyrrolidone Optimized Vacuum-Flash.

Efficiency reduction in perovskite solar cells (PSCs) during the magnification procedure significantly hampers commercialization. Vacuum-flash (VF) has emerged as a promising method to fabricate PSCs with consistent efficiency across scales. However, the slower solvent removal rate of VF compared to the anti-solvent method leads to perovskite films with buried defects. Thus, this work employs low-toxic Lewis base ligand solvent N-ethyl-2-pyrrolidone (NEP) to improve the nucleation process of perovskite films. NEP, with a mechanism similar to that of N-methyl-2-pyrrolidone in FA-based perovskite formation, enhances the solvent removal speed owing to its lower coordination ability. Based on this strategy, p-i-n PSCs with an optimized interface attain a power conversion efficiency (PCE) of 24.19% on an area of 0.08 cm2. The same nucleation process enables perovskite solar modules (PSMs) to achieve a certified PCE of 23.28% on an aperture area of 22.96 cm2, with a high geometric fill factor of 97%, ensuring nearly identical active area PCE (24%) in PSMs as in PSCs. This strategy highlights the potential of NEP as a ligand solvent choice for the commercialization of PSCs.

Hydroxyl-Bonded Co Single Atom Site on Boroncarbonitride Surface Realizes Non-sacrificial H2O2 Synthesis in the Near-Infrared Region.

Photocatalytic synthesis of hydrogen peroxide (H2O2) from O2 and H2O under near-infrared light is a sustainable renewable energy production strategy, but challenging reaction. The bottleneck of this reaction lies in the regulation of O2 reduction path by photocatalyst. Herein, we construct the center of the one-step two-electron reduction (OSR) pathway of O2 for H2O2 evolution via the formation of the hydroxyl-bonded Co single-atom sites on boroncarbonitride surface (BCN-OH2/Co1). Our experimental and theoretical prediction results confirm that the hydroxyl group on the surface and the electronic band structure of BCN-OH2/Co1 are the key factor in regulating the O2 reduction pathway. In addition, the hydroxyl-bonded Co single-atom sites can further enrich O2 molecules with more electrons, which can avoid the one-electron reduction of O2 to •O2 -, thus promoting the direct two-electron activation hydrogenation of O2. Consequently, BCN-OH2/Co1 exhibited a high H2O2 evolution apparent quantum efficiency of 0.8% at 850nm, better than most of the previously reported photocatalysts. This study reveals an important reaction pathway for the generation of H2O2, emphasizing that precise control of the active site structure of the photocatalyst is essential for achieving efficient conversion of solar-to-chemical. This article is protected by copyright. All rights reserved.