Adjacent Active Sites Research Articles

Mild and rapid construction of Ti electrodes for efficient and corrosion-resistant oxidative catalysis at industrial-grade intensity

The development of cost-effective and corrosion-resistant catalytic electrodes for chlorine/oxygen evolution reaction (CER/OER) in large-scale industrial applications is a significant challenge. Herein, the sol–gel method is employed to achieve a uniform coating of ruthenium (Ru) doping copper (Cu) on titanium sheet (Ru + 20 %Cu@Ti), and the highly efficient industrial grade stable Ti dimensional stable anode can be quickly constructed at 723.15 K for 2 h. Cu doping reduces the vacancy formation energy of surface oxygen, promotes additional lattice oxygen vacancy assisted hydrolysis dissociation pathway, improves the selectivity and specific activity of CER at high concentration doping, and reduces the binding energy of OER intermediates (e.g., *OH, *O, and *OOH) at adjacent Ru active sites. The overpotentials require to reach the current density of 10 mA cm−2 for CER and OER were only 365 mV and 232 mV at the conditions of 5.0 M NaCl (pH = 7.0) and 1.0 M KOH + 0.5 M NaCl. More importantly, Ru + 20 %Cu@Ti demonstrates excellent stability, operates continuously for over 340h at industrial current density in neutral and alkaline electrolytes, and its strengthening life reaches 64 h, with ultra-low performance attenuation. Impressively, the designed applied electrode (8.0 cm ✕ 15.0 cm) achieves long-term CER at 0.2–0.3 A cm−2. Further industrial grade evaluation of CER shows that its chlorine extraction polarizability, enhances life and weight loss meet the requirements of industrial applications.

Layered Porous Ring-Like Carbon Network Protected FeNi Metal Atomic Pairs for Bifunctional Oxygen Electrocatalysis and Rechargeable Zn-Air Batteries.

Bimetallic atom catalysts exhibit ultra-high oxygen electrocatalytic activity by harnessing mutual promotion and synergistic effects between adjacent metal active centers, surpassing the performance of single metal atomic catalysts. Herein, FeNi atom pairs protected by hierarchical porous annular carbon grids (P-FeNi-NPC) are introduced using a mediator-assisted MOFs-derived strategy. The introduction of the multi-block copolymer P123 ensures the uniform confinement and dispersion of metal ions, followed by thermal decomposition to form a "planetary-ring-like" carbon framework that anchors the bimetallic atomic pairs in the active region. The homogeneous distribution of adjacent Fe-N4 and Ni-N4 active sites significantly enhances catalytic activity and stability. Leveraging unique electronic and geometric structures, the resulting P-FeNi-NPC catalyst demonstrates exceptional ORR and OER activities with an ΔE value of 0.705 (E1/2 = 0.845V, Ej = 10 = 1.55V). Theoretical calculations unveil that FeNi bimetallic sites loaded on nitrogen-doped carbon frameworks with specific curvature effectively modulate the energy of d-band centers, thus balancing the free energy of oxygen-containing intermediates. This study presents a novel and versatile approach for synthesizing advanced bifunctional catalysts, poised to drive the future development of Zn-air batteries.

Adjacent Reaction Sites of Atomic Mn2O3 and Oxygen Vacancies Facilitate CO2 Activation for Enhanced CH4 Production on TiO2-Supported Nickel-Hydroxide Nanoparticles

The catalytic conversion of carbon dioxide (CO2) to methane (CH4) through the “Sabatier reaction”, also known as CO2 methanation, presents a promising avenue for establishing a closed carbon loop. However, the competitive reverse water gas shift (RWGS) reaction severely limits CH4 production at lower temperatures; therefore, developing highly efficient and selective catalysts for CO2 methanation is imperative. In this regard, we have developed a novel nanocatalyst comprising atomic scale Mn2O3 species decorated in the defect sites of TiO2-supported Ni-hydroxide nanoparticles with abundant oxygen vacancies (hereafter denoted as NiMn-1). The as-prepared NiMn-1 catalyst initiates the CO2 methanation at a temperature of 523 K and delivers an optimal CH4 production yield of 21,312 mmol g−1 h−1 with a CH4 selectivity as high as ~92% at 573 K, which is 45% higher as compared to its monometallic counterpart Ni-TiO2 (14,741 mmol g−1 h−1). Physical investigations combined with gas chromatography analysis corroborate that the exceptional activity and selectivity of the NiMn-1 catalyst stem from the synergistic cooperation between adjacent active sites on its surface. Specifically, the high density of oxygen vacancies in Ni-hydroxide and adjacent Mn2O3 domains facilitate CO2 activation, while the metallic Ni domains trigger H2 splitting. We envision that the obtained results pave the way for the design of highly active and selective catalysts for CO2 methanation.

Insightful Understanding of Synergistic Oxygen Reduction on PtCo3(111) Toward Zinc-Air Batteries.

Theory-guided materials design is an effective strategy for designing catalysts with high intrinsic activity whilst minimizing the usage of expensive metals like platinum. As proof-of-concept, herein it demonstrates that using density functional theory (DFT) calculations and experimental validation that intermetallic PtCo3 alloy nanoparticles offer enhanced electrocatatalytic performance for the oxygen reduction reaction (ORR) compared to Pt nanoparticles. DFT calculations established that PtCo3(111) surfaces possess better intrinsic ORR activity compared to Pt(111) surfaces, owing to the synergistic action of adjacent Pt and Co active sites which optimizes the binding strength of ORR intermediates to boost overall ORR kinetics. With this understanding, a PtCo3/NC catalyst, comprising PtCo3 nanoparticles exposing predominantly (111) facets dispersed on an N-doped carbon support, is successfully fabricated. PtCo3/NC demonstrates a high specific activity (3.4mAcm-2mgPt -1), mass activity (0.67AmgPt -1), and cycling stability for the ORR in 0.1M KOH, significantly outperforming a commercial 20wt.% Pt/C catalyst. Moreover, a zinc-air battery (ZAB) assembled with PtCo3/NC as the air-electrode catalyst delivered an open-circuit voltage of 1.47V, a specific capacity of 775.1mAhgZn -1 and excellent operation durability after 200 discharge/charge cycles, vastly superior performance to a ZAB built using commercial Pt/C+IrO2 as the air-electrode catalyst.

Dual single atomic Fe-Ni sites in N‑doped nanoporous carbon for high-efficiency potassium periodate activation toward pollutant abatement

Diatomic catalysts (DACs) with atomically isolated metal pairs hold the potential for activating potassium periodate (PI) in sustainable pollution control, yet their synthesis poses a significant challenge. In this study, Fe/Ni species anchored to a nitrogen-doped carbon as diatomic catalysts (FeNi-NC DACs) were precisely synthesized by direct carbonization of metal–organic frameworks (MOFs) assembled by Fe/Ni-doped ZnO nanoparticles and used for the effective decomposition of organic pollutants through PI activation. As anticipated, FeNi-NC exhibited superior catalytic properties due to the abundance of adjacent bimetallic active sites (Fe/Ni-Nx), rich doped nitrogen, high specific surface area, and electron transport conductivity, surpassing single-atom Fe-NC and Ni-NC, as well as nonmetallic NC catalysts. Free radical quenching, electron paramagnetic resonance, and electrochemical experiments have shown that the FeNi-NC/PI system can oxidize organic compounds through non-free radical oxidation pathways, including singlet oxygen (1O2) oxidation and mediated electron transfer processes. Electron transfer mediated by FeNi-NC/PI* complexes is the primary mechanism for organic oxidation. Additionally, the FeNi-NC catalyst demonstrated remarkable stability in both inorganic-containing and real water samples, as well as in continuous-flow microreactors. This study introduces a novel approach for designing highly efficient DACs and offers fundamental insights into the mechanism of PI-activated oxidation of organic pollutants.

Boosting Formate Electrooxidation by Heterostructured PtPd Alloy and Oxides Nanowires.

Direct formate fuel cells (DFFCs) receive increasing attention as promising technologies for the future energy mix and environmental sustainability, as formate can be made from carbon dioxide utilization and is carbon neutral. Herein, heterostructured platinum-palladiumalloy and oxides nanowires (PtPd-ox NWs) with abundant defect sites are synthesized through a facile self-template method and demonstrated high activity toward formate electrooxidation reaction (FOR). The electronic tuning arising from the heterojunction between alloy and oxides influence the work function of PtPd-ox NWs. The sample with optimal work function reveals the favorable adsorption behavior for intermediates and strong interaction in the d-p orbital hybridization between Pt site and oxygen in formate, favoring the FOR direct pathway with a low energy barrier. Besides the thermodynamic regulation, the heterostructure can also provide sufficient hydroxyl species to facilitate the formation of carbon dioxide due to the ability of combining absorbed hydrogen and carbon monoxide at adjacent active sites, which contributes to the improvement of FOR kinetics on PtPd-ox NWs. Thus, heterostructured PtPd-ox NWs achieve dual regulation of FOR thermodynamics and kinetics, exhibiting remarkable performance and demonstrating potential in practical systems.

Revealing Distance-Dependent Synergy between MnCo2O4 and Co-N-C in Boosting the Oxygen Reduction Reaction.

Synergistic effects have been applied to a variety of hybrid electrocatalysts to improve their activity and selectivity. Understanding the synergistic mechanism is crucial for the rational design of these types of catalysts. Here, we synthesize a MnCo2O4/Co-N-C hybrid electrocatalyst for the oxygen reduction reaction (ORR) and systematically investigate the synergy between MnCo2O4 nanoparticles and Co-N-C support. Theoretical simulations reveal that the synergy is closely related to the distance between active sites. For a pair of remote active sites, the ORR proceeds through the known 2e- + 2e- relay catalysis while the direct 4e- ORR occurs on a pair of adjacent active sites. Therefore, the formation of the undesired byproduct (H2O2) is inhibited at the interface region between MnCo2O4 and Co-N-C. This synergistic effect is further verified on an anion-exchange membrane fuel cell. The findings deepen the understanding of synergistic catalysis and will provide guidance for the rational design of hybrid electrocatalysts.

Phosphorus doping to promote the reconstruction of NiS nanorods for efficient electrocatalytic water oxidation

Transition metal sulfides have been verified as effective precatalysts for OER in alkaline conditions, and the in-situ reconstructed metal (oxy)hydroxides on their surface were the real active sites. The rational reconstruction can regulate the amount and chemical state of the metal (oxy)hydroxides and thus promote the OER performance efficiently, but also remains a challenge. Herein, we report a unique rationally controllable in-situ anodic electrochemical activation (AEA) strategy to promote the surface reconstruction for the formation of amorphous NiOOH layer onto the P-doped NiS nanorod arrays on nickel foam (P-NiS@NiOOH-aea/NF). The doping of P atom promotes the dissolution of S and accelerates the reconstitution of NiOOH on its surface. The optimized P-NiS@NiOOH-aea/NF through the unique AEA strategy exhibits outstanding OER activity requiring ultra-low overpotentials of 203 and 349 mV to reach 10 and 1000 mA cm−2, respectively, together with robust electrocatalytic stability and satisfactory selectivity (nearly 100% Faraday efficiency) in 1.0 M KOH solution. The density functional theory (DFT) calculations further demonstrate that heteroatomic P-doping reduces the adsorption free energy of intermediate species and enhances the OER intrinsic activity of adjacent nickel active site. This work has a guiding significance for the rational design of introducing anions in the in-situ reconstruction process.

Continuous Phase Regulation of a Pd-Te Hexagonal Nanoplate Library.

Phase regulation of noble metal-based nanomaterials provides a promising strategy for boosting the catalytic performance. However, realizing the continuous phase modulation in two-dimensional structures and unveiling the relevant structure-performance relationship remain significant challenges. In this work, we present the first example of continuous phase modulation in a library of Pd-Te hexagonal nanoplates (HNPs) from cubic-phase Pd4Te, rhombohedral-phase Pd20Te7, rhombohedral-phase Pd8Te3, and hexagonal-phase PdTe to hexagonal-phase PdTe2. Notably, the continuous phase regulation of the well-defined Pd-Te HNPs enables the successful modulation of the distance between adjacent Pd active sites, triggering an exciting way for tuning the relevant catalytic reactions intrinsically. The proof-of-concept oxygen reduction reaction (ORR) experiment shows a Pd-Pd distance-dependent ORR performance, where the hexagonal-phase PdTe HNPs present the best electrochemical performance in ORR (mass activity and specific activity of 1.02 A mg-1Pd and 1.83 mA cm-2Pd at 0.9 V vs RHE). Theoretical investigation reveals that the increased Pd-Pd distance relates to the weak *OH adsorption over Pd-Te HNPs, thus contributing to the remarkable ORR activity of PdTe HNPs. This work advances the phase-controlled synthesis of noble metal-based nanostructures, which gives huge impetus to the design of high-efficiency nanomaterials for diverse applications.

High-performance carbon dioxide reduction to multi-carbon products on EDTA-modified Cu–Ag tandem catalyst

Tandem catalysts are able to sequential reduction of CO2 to multi-carbon (C2+) on their adjacent complement hetero active sites. However, Faraday efficiency of C2+ on these catalysts is limited by inefficient modulation of local pH. Herein, we systematically design ethylenediaminetetraacetic acid (EDTA) modified Cu–Ag catalysts for reduction of CO2 to C2+ products with highly selectivity. After introducing EDTA, surface Cu atoms possess well-defined valence and coordination environments, giving improved electronic configuration for intermediate adsorption. During electrochemical reaction, amine groups shows strong ability to regulate local pH and thus facilitates reaction kinetics. Correspondingly, several important intermediates that related to formation of C2+ on adjacent active sites are observed in in-situ Raman spectra. CuAg4/EDTA shows high activity for C2+ products, with total FEC2+ of 86.56 % at applied potential of −1.23 V vs. RHE. This unique protocol is expected to provide a scientific basis for expanding functional ligand in regulating microenvironment of catalysts.

Can HOCl be superficially stabilized on an electrocatalyst as proposed in the active chlorine mechanism involving •OH radicals?: Beyond the Cl2 evolution

According to Comninellis’ proposal on water oxidation, anodes physisorbing active oxygen readily form •OH radicals to develop electrocombustion processes, while electrode surfaces forming the so-called higher oxide MO x+1 chemisorb active oxygen, being more prone to perform the O2 evolution reaction (OER). Here, we adopt a similar premise to account for the active chlorine mechanism (ACM), assuming that the capacity of an electrocatalyst to physisorb/chemisorb active oxygen determines the type of chlorine species formed and stabilized. Density Functional Theory (DFT) calculations are conducted to evaluate the stability of HOCl, OCl and OCl --H+ species oxidant species on Boron Doped Diamond (BDD), and rutile-type surfaces (110 plane) of SnO2, TiO2, PbO2, RuO2, and IrO2, in the absence and presence of H2O molecules. The computed relaxed models reveal that SnO2 and PbO2 physisorbing active oxygen are only able to stabilize OCl-ads species on pentacoordinated transition metal atoms (M5c); whereas RuO2, and IrO2 chemisorbing active oxygen produce Clads- on an adjacent M5c active site. The BDD surface is the only surface able to maintain the HOCl stability with and without H2O solvation. Thus, it is proposed that BDD and TiO2, physisorbing active oxygen, preferentially adopt a 2-electron transfer step to generate (HOCl)ads; while SnO2 and PbO2, with moderate physisorption, also follow a 2-electron transfer step but produced (OCl-)ads and (H+)ads, thus dissociating (HOCl)ads. RuO2 and IrO2, preferentially forming the so-called higher oxide MOx+1, adopt a 3-electron transfer step to either produce (OCl)ads, or (O)ads + (Cl)ads, where there is a more equal competition towards the oxygen evolution.

Precise Anchoring of Fe Sites by Regulating Crystallinity of Novel Binuclear Ni-MOF for Revealing Mechanism of Electrocatalytic Oxygen Evolution.

Bimetallic metal-organic framework (BMOF) exhibits better electrocatalytic performance than mono-MOF, but deciphering the precise anchoring of foreign atoms and revealing the underlying mechanisms at the atomic level remains a major challenge. Herein, a novel binuclear NiFe-MOF with precise anchoring of Fe sites is synthesized. The low-crystallinity (LC)-NiFe0.33 -MOF exhibited abundant unsaturated active sites and demonstrated excellent electrocatalytic oxygen evolution reaction (OER) performance. It achieved an ultralow overpotential of 230mV at 10mAcm-2 and a Tafel slope of 41mVdec-1 . Using a combination of modulating crystallinity, X-ray absorption spectroscopy, and theoretical calculations, the accurate metal sequence of BMOF and the synergistic effect of the active sites are identified, revealing that the adjacent active site plays a significant role in regulating the catalytic performance of the endmost active site. The proposed model of BMOF electrocatalysts facilitates the investigation of efficient OER electrocatalysts and the related catalytic mechanisms.

Binary and nanostructured Ni[sbnd]Mn perovskite fluorides as efficient electrocatalysts for urea oxidation reaction

Urea electrolysis holds tremendous promise to provide green and sustainable energy and environmental solutions, because it can simultaneously remedy urea–containing wastewater and provide energy–saving hydrogen. However, the development of this emerging technology remains challenging mainly due to a dearth of high–performance electrocatalysts for efficient urea oxidation reaction (UOR). Perovskite fluorides have the advantages of intrinsic 3D diffusion pathways, robust architecture, and tunable chemical composition, thus receiving increasing attention in many applications. In this work, the UOR performances of a series of ABF3 samples (A = K; B = Ni/Mn, Ni/Co, Co/Mn) with various compositions are investigated in a systematic fashion for the first time. Among the binary samples, KNMF41 (Ni/Mn atomic ratio = 4:1) is the optimal sample with reduced overpotential (reaching 100 mA cm−2 at 1.43 V), low Tafel slope (40 mV dec−1), enhanced reaction rate constant (6.3 × 105 cm3 mol−1 s−1), and high turnover frequency (TOF, 0.19 s−1 at 1.60 V) toward urea oxidation. By comparing with NiCo and CoMn samples, the binary NiMn design is confirmed to endow the perovskite fluoride with higher electrocatalytic activity, thanks to the directed adsorption of urea molecules on the adjacent NiMn active sites. This work presents a targeted synthetic strategy for obtaining efficient electrocatalysts.

Precision tuning of highly efficient Pt-based ternary alloys on nitrogen-doped multi-wall carbon nanotubes for methanol oxidation reaction

The electrochemical methanol oxidation is a crucial reaction in the conversion of renewable energy. To enable the widespread adoption of direct methanol fuel cells (DMFCs), it is essential to create and engineer catalysts that are both highly effective and robust for conducting the methanol oxidation reaction (MOR). In this work, trimetallic PtCoRu electrocatalysts on nitrogen-doped carbon and multi-wall carbon nanotubes (PtCoRu@NC/MWCNTs) were prepared through a two-pot synthetic strategy. The acceleration of CO oxidation to CO2 and the blocking of CO reduction on adjacent Pt active sites were attributed to the crucial role played by cobalt atoms in the as-prepared electrocatalysts. The precise control of Co atoms loading was achieved through precursor stoichiometry. Various physicochemical techniques were employed to analyze the morphology, element composition, and electronic state of the catalyst. Electrochemical investigations and theoretical calculations confirmed that the Pt1Co3Ru1@NC/MWCNTs exhibit excellent electrocatalytic performance and durability for the process of MOR. The enhanced MOR activity can be attributed to the synergistic effect between the multiple elements resulting from precisely controlled Co loading content on surface of the electrocatalyst, which facilitates efficient charge transfer. This interaction between the multiple components also modifies the electronic structures of active sites, thereby promoting the conversion of intermediates and accelerating the MOR process. Thus, achieving precise control over Co loading in PtCoRu@NC/MWCNTs would enable the development of high-performance catalysts for DMFCs.

Triethylenediamine cobalt complex encapsulated in a metal–organic framework cage to prepare a cobalt single-atom catalyst with a high Co-N4 density for an efficient oxygen reduction reaction

Transition metal single atom catalysts (TM SACs) are the most promising oxygen reduction reaction (ORR) catalysts for proton exchange membrane fuel cells (PEMFCs) and metal-air batteries. However, the low density of M-Nx active sites seriously hinders further improvement of the ORR electrocatalytic activity. Here, a strategy for encapsulating nitrogen-rich guest molecules (triethylenediamine cobalt complex, [Co(en)3]3+) was proposed to construct a high-performance cobalt single-atom catalyst (Co-encapsulated SAC/NC). With this strategy, the guest molecules are encapsulated into metal–organic framework (MOF) cages as an additional cobalt source to boost cobalt loading, while abundant nitrogen from guest molecules contributes to the formation of Co-N4 active sites. Remarkably, the resulting Co-encapsulated SAC/NC has a high cobalt loading amount of 4.03 wt%, and spherical aberration-corrected transmission electron microscopy (AC-TEM) has confirmed that most cobalt exists in a single-atom state. As a result, the Co-encapsulated SAC/NC exhibits excellent ORR catalytic performance with a half-wave potential of 0.88 V. Furthermore, Zn-air batteries employing Co-encapsulated SAC/NC as air cathode show high peak power density and excellent cycling stability. Density functional theory (DFT) calculations reveal that adjacent active sites have different rate-determining steps and lower reaction energy barriers than a single active site.

Proximity effects in graphene-supported single-atom catalysts for hydrogen evolution reaction.

The interaction between adjacent active sites is crucial to balance the efficiency and utilization of functional atoms in single-atom catalysts. Herein, the catalytic activity of hydrogen evolution reaction at different site (nitrogen coordinated transition metal centers embedded in graphene) distances was comprehensively investigated by density functional theory calculations. The results show that a proximity effect of reactivity and site spacing can be identified in the Co-series single-atom catalysts. Although the proximity effect is more linearly responded with the site spacing along x direction, an optimal distance of ∼0.8 and ∼2.8nm are found for Co and Rh, Ir atoms, respectively. An in-depth analysis of the electronic property reveals that the proximity effect is caused by the distinct net charge of the active site, which is affected by the dz2 position relative to EF. Subsequently, an excess electron nodal channel in x direction was found to serve as a communication pathway between the active sites. Through the finding in this work, an optimal Fe-N2C2 structure was deliberately designed and has shown prominent proximity effect as Co-series do. The results reported in this work provide a simple and effective tuning method for the reactivity of a single-atom catalyst.

Bifunctional Lewis acid-base nanocatalysts with dual active sites for strengthened coupling of alcohol conversion and H2 evolution

The synergistic of organic transformation with H2 production in one redox cycle is highly desirable to achieve the full use of photogenerated holes and electrons but challenging. Herein, Lewis acid-base nanocatalysts in which Ni decorated defective ZnIn2S4 (denoted as Ni/VZIS) has been prepared through photodeposition with Zn defective ZnIn2S4 nanosheets as precursor. The Zn vacancies favors the selective deposition of Ni, enabling the co-exposure of Lewis acid Ni and Lewis base S adjacent dual active sites. In-situ FTIR results reveal the coexistence of Ni and Zn vacancy on ZnIn2S4 favored the chemisorption of benzyl alcohol. The electron-deficient Ni Lewis acid (LA) site and electron-rich S Lewis base (LB) site can act as benzyl alcohol conversion and H2 evolution sites, respectively, thus facilitating the full use of photoinduced electrons and holes. The spectroscopy and photoelectrochemical studies demonstrate the transfer and separation of photogenerated carries are also facilitated in the nanohybrids. As such, the Ni/VZIS photocatalyst show outstanding performance of photocatalytic conversion benzyl alcohol (BA) into benzaldehyde (BAD) and H2, with the optimal H2 generation rate of 81.9 μmol h−1, accompanying benzaldehyde generation rate of 73.7 μmol h−1. This work provides a profound insight into the designing of multi-functionalized nanohybrids for the full use of photoexcited electrons-holes pairs.

Adjacent Copper Single Atoms Promote C-C Coupling in Electrochemical CO2 Reduction for the Efficient Conversion of Ethanol.

The electrochemical CO2 reduction reaction (CO2RR) using renewable electricity is one of the most promising strategies for reaching the goal of carbon neutrality. Multicarbonous (C2+) products have broad applications, and ethanol is a valuable chemical and fuel. Many Cu-based catalysts have been reported to be efficient for the electrocatalytic CO2RR to C2+ products, but they generally offer limited selectivity and current density toward ethanol. Herein, we proposed a silica-mediated hydrogen-bonded organic framework (HOF)-templated approach to preparing ultrahigh-density Cu single-atom catalysts (SACs) on thin-walled N-doped carbon nanotubes (TWN). The content of Cu in the catalysts prepared by this method could be up to 13.35 wt %. It was found that the catalysts showed outstanding performance for the electrochemical CO2RR to ethanol, and the Faradaic efficiency (FE) of ethanol increased with the increase in Cu-N3 site density. The FE of ethanol over the catalysts with 13.35 wt % Cu could reach ∼81.9% with a partial current density of 35.6 mA cm-2 using an H-type cell, which is the best result for electrochemical CO2RR to ethanol to date. In addition, the catalyst could be stably used for more than 25 h. Experimental and density functional theory (DFT) studies revealed that the adjacent Cu-N3 active sites (one Cu atom coordinates with three N) were the active sites for the reaction, and their high density was crucial for the high FE of ethanol because the adjacent Cu-N3 sites with a short distance could promote the C-C coupling synergistically.

B atom dopant-manipulate electronic structure of CuIn nanoalloy delivering wide potential activity over electrochemical CO2RR

The accuracy and efficiency tuning the local electronic structure of catalyst active sites are pre-requisites for achieving high selectivity CO2 reduction reaction on a wide potential window, whereas remain a great challenge. Here, a B-doped CuIn alloy catalyst with tunable electronic structure for the highly effective electrochemical conversion of CO2 to CO has been exploited. The obtained B-doped CuIn alloy performs an optimal CO Faraday efficiency of 99% at –0.6 V (vs. the reversible hydrogen electrode) and particularly keeps outstanding CO Faraday efficiency (> 90%) over a wide cathodic electrochemical window (400 mV). Density functional theory theoretical calculation manifests that the enhanced performance is primarily ascribed to the electron-capturing ability of high valence state B atom, which optimizes the local electronic structure of adjacent metal active sites and adjusts the binding energy between catalyst and intermediates. A foundation of designing advanced electrochemical CO2 reduction reaction catalysts can be served by the insights gained though this research.

Proximity of defects and Ti-H on hydrogenated SrTiO3 mediated photocatalytic reduction of CO2 to C2H2

Photocatalytic converting CO2 into C2 products is highly desirable but is extremely sensitive to catalyst structure. In this work, Ti-H species and oxygen vacancies are simultaneously integrated on hydrogenated SrTiO3 surface by thermally treating with NaBH4, which promotes the activation of CO2 into HCOO- and CO* intermediates. The proximity of oxygen vacancies and Ti-H species contributes to the C-C coupling of intermediates into acetylene (C2H2) products. To the best of our knowledge, this is the first example for the photocatalytic CO2 reduction into C2H2 main products. The optimal hydrogenated SrTiO3 has the C2H2 yield of 39.0 μmol·g−1 with a 76.0 % selectivity among C2 products. Therefore, this work provides an approach of designing the adjacent active sites for photocatalytic CO2 conversion into C2+ products.