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Electroreduction of CO2 into multi-carbon (C2+) products (e.g. C2+ alcohols) offers a promising way for CO2 utilization. Use of strong alkaline electrolytes is favorable to producing C2+ products. However, CO2 can react with hydroxide to form carbonate/bicarbonate, which results in low carbon utilization efficiency and poor stability. Using acidic electrolyte is an efficient way to solve the problems, but it is a challenge to achieve high selectivity of C2+ products. Here we report that the amine modified copper nanoparticles exhibit high selectivity of C2+ products and carbon utilization at acidic condition. The Faradaic efficiency (FE) of C2+ products reach up to 81.8% at acidic media (pH=2) with a total current density of 410 mA cm-2 over n-butylamine modified Cu. Especially the FE of C2+ alcohols is 52.6%, which is higher than those reported for CO2 electroreduction at acidic condition. In addition, the single-pass carbon efficiency towards C2+ production reach up to 60%. Detailed studies demonstrate that the amine molecule on the surface of Cu cannot only enhance the formation, adsorption and coverage of *CO, but also provide a hydrophobic environment, which result in the high selectivity of C2+ alcohols at acidic condition., (© 2024 Wiley‐VCH GmbH.)

Single-metal atomic sites and vacancies can accelerate the transfer of photogenerated electrons and enhance photocatalytic performance in photocatalysis. In this study, a series of nickel hydroxide nanoboards (Ni(OH) x NBs) with different loadings of single-atomic Ru sites (w-SA-Ru/Ni(OH) x ) were synthesized via a photoreduction strategy. In such catalysts, single-atomic Ru sites are anchored to the vacancies surrounding the pits. Notably, the SA-Ru/Ni(OH) x with 0.60 wt % Ru loading (0.60-SA-Ru/Ni(OH) x ) exhibits the highest catalytic performance (27.6 mmol g -1  h -1 ) during the photocatalytic reduction of CO 2 (CO 2 RR). Either superfluous (0.64 wt %, 18.9 mmol g -1  h -1 ; 3.35 wt %, 9.4 mmol -1  h -1 ) or scarce (0.06 wt %, 15.8 mmol g -1  h -1 ; 0.29 wt %, 21.95 mmol g -1  h -1 ; 0.58 wt %, 23.4 mmol g -1  h -1 ) of Ru sites have negative effect on its catalytic properties. Density functional theory (DFT) calculations combined with experimental results revealed that CO 2 can be adsorbed in the pits; single-atomic Ru sites can help with the conversion of as-adsorbed CO 2 and lower the energy of *COOH formation accelerating the reaction; the excessive single-atomic Ru sites occupy vacancies that retard the completion of CO 2 RR., (© 2024 Wiley-VCH GmbH.)

Constructing electrocatalysts with p-block elements is generally considered rather challenging owing to their closed d shells. Here for the first time, we present a p-block-element bismuth-based (Bi-based) catalyst with the co-existence of single-atomic Bi sites coordinated with oxygen (O) and sulfur (S) atoms and Bi nanoclusters (Bi clu ) (collectively denoted as BiOS SA /Bi clu ) for the highly selective oxygen reduction reaction (ORR) into hydrogen peroxide (H 2 O 2 ). As a result, BiOS SA /Bi clu gives a high H 2 O 2 selectivity of 95 % in rotating ring-disk electrode, and a large current density of 36 mA cm -2 at 0.15 V vs. RHE, a considerable H 2 O 2 yield of 11.5 mg cm -2 h -1 with high H 2 O 2 Faraday efficiency of ∼90 % at 0.3 V vs. RHE and a long-term durability of ∼22 h in H-cell test. Interestingly, the experimental data on site poisoning and theoretical calculations both revealed that, for BiOS SA /Bi clu , the catalytic active sites are on the Bi clusters, which are further activated by the atomically dispersed Bi coordinated with O and S atoms. This work demonstrates a new synergistic tandem strategy for advanced p-block-element Bi catalysts featuring atomic-level catalytic sites, and the great potential of rational material design for constructing highly active electrocatalysts based on p-block metals., (© 2023 Wiley-VCH Verlag GmbH.)

In photosynthesis, solar energy is harvested by photosensitizers, and then, the excited electrons transfer via a Z-Scheme mode to enzymatic catalytic centers to trigger redox reactions. Herein, we constructed a core-shell Z-scheme heterojunction of semiconductor@single-atom catalysts (SACs). The oxygen-vacancy-rich ZnO core and single-atom Co-N 4 sites supported on nitrogen-rich carbon shell (SA-Co-CN) act as the photosensitizer and the enzyme-mimicking active centers, respectively. Driven by built-in electric field across the heterojunction, photoexcited electrons could rapidly (2 ps) transfer from the n-type ZnO core to the p-type SA-Co-CN shell, finally boosting the catalytic performance of the surface-exposed single-atom Co-N 4 sites for peroxymonosulfate (PMS) activation under light irradiation. The synergies between photocatalysis and heterogeneous Fenton-like reaction lead to phenomenally enhanced production of various reactive oxygen species for rapid degradation of various microcontaminants in water. Experimental and theoretical results validate that the interfacial coupling of SA-Co-CN with ZnO greatly facilitates PMS adsorption and activation by reducing the adsorption energy and enhancing the cascade electron transfer processes for the photo-Fenton-like reaction., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The two-dimensional nanosheets are conducive to not only endow opened surfaces for loading active metal atoms but also boost the mass transfer for the heterogeneous reactions. The challenge is how to load and stabilize single-atoms on nanosheets in high-areal densities. This work reports an efficient micro-gas blasting (MGB) strategy to access versatile noble metal single-atoms/metal oxide nanosheets, including Ir 1 /CoO x , Pd 1 /CeO 2 , etc. Especially for Pt/CeO 2 nanosheets (Pt 1 /CeO 2 -S), the Pt loading is increased to 15 at%. The Pt 1 /CeO 2 -S catalysts from MGB are revealed to possess superior reactivity and tolerance in the model reaction of water-gas shift (WGS). The Pt 1 /CeO 2 -S catalyst exhibit 2-3 times reactivity that of their thicker counterpart, single-atom Pt 1 /CeO 2 microspheric catalyst. Moreover, the single-atom sites in Pt 1 /CeO 2 -S (1-10 %) catalysts are stable in a harsh WGS reaction condition of 10 % CO. This work thus paves a way to access the practical single-atom catalysts., (© 2022 Wiley-VCH GmbH.)

Developing electrocatalytic reactions with high-efficiency can make important contributions to carbon neutrality. However, poor long-term stability of catalysts is a bottleneck for its practical application. Herein, an "in situ periodic regeneration of catalyst (PR-C)" strategy is proposed to give long-term high efficiency of CO 2 electroreduction to generate C 2+ products over Cu catalyst by applying a positive potential pulse for a short time periodically in the halide-containing electrolyte. The high Faradaic efficiency (81.2 %) and current density (22.6 mA cm -2 ) could be maintained completely at least 36 h, while the activity and selectivity decreased continuously without using the PR-C method. Control experiments and operando characterization demonstrated that the surface structure and oxidation state of Cu could be recovered periodically by the PR-C method, which was beneficial for CO 2 activation and C-C coupling., (© 2022 Wiley-VCH GmbH.)

Electroreduction of CO 2 into valuable fuels and feedstocks offers a promising way for CO 2 utilization. However, the commercialization is limited by the low productivity. Here, we report a strategy to enhance the productivity of CO 2 electroreduction by improving diffusion of CO 2 to the surface of catalysts using porous organic cages (POCs) as an additive. It was noted that the Faradaic efficiency (FE) of C2+ products could reach 76.1 % with a current density of 1.7 A cm -2 when Cu-nanorod(nr)/CC3 (one of the POCs) was used, which were much higher than that using Cu-nr. Detailed studies demonstrated that the hydrophobic pores of CC3 can adsorb a large amount of CO 2 for the reaction, and the diffusion of CO 2 in the CC3 to the nanocatalyst surface is easier than that in the liquid electrolyte. Thus, more CO 2 molecules make contact with the nanocatalysts in the presence of CC3, enhancing CO 2 reduction and inhibiting generation of H 2 ., (© 2022 Wiley-VCH GmbH.)

Electrocatalytic reduction of CO 2 (CO 2 RR) to value-added chemicals is of great significance for CO 2 utilization, however the CO 2 RR process involving multi-electron and proton transfer is greatly limited by poor selectivity and low yield. Herein, We have developed an atomically dispersed monovalent zinc catalyst anchored on nitrogenated carbon nanosheets (Zn/NC NSs). Benefiting from the unique coordination environment and atomic dispersion, the Zn/NC NSs exhibit a superior CO 2 RR performance, featuring a high current density up to 50 mA cm -2 with an outstanding CO Faradaic efficiency of ≈95 %. The center Zn I atom coordinated with three N atoms and one N atom that bridges over two adjacent graphitic edges (Zn-N 3+1 ) is identified as the catalytically active site. Experimental results reveal that the twisted Zn-N 3+1 structure accelerates CO 2 activation and protonation in the rate-determining step of *CO 2 to *COOH, while theoretical calculations elucidate that atomically dispersed Zn-N 3+1 moieties decrease the potential barriers for intermediate COOH* formation, promoting the proton-coupled CO 2 RR kinetics and boosting the overall catalytic performance., (© 2021 Wiley-VCH GmbH.)

Using renewable electricity to drive CO 2 electroreduction is an attractive way to achieve carbon-neutral energy cycle and produce value-added chemicals and fuels. As an important platform molecule and clean fuel, methanol requires 6-electron transfer in the process of CO 2 reduction. Currently, CO 2 electroreduction to methanol suffers from poor efficiency and low selectivity. Herein, we report the first work to design atomically dispersed Sn site anchored on defective CuO catalysts for CO 2 electroreduction to methanol. It exhibits high methanol Faradaic efficiency (FE) of 88.6 % with a current density of 67.0 mA cm -2 and remarkable stability in a H-cell, which is the highest FE(methanol) with such high current density compared with the results reported to date. The atomic Sn site, adjacent oxygen vacancy and CuO support cooperate very well, leading to higher double-layer capacitance, larger CO 2 adsorption capacity and lower interfacial charge transfer resistance. Operando experiments and density functional theory calculations demonstrate that the catalyst is beneficial for CO 2 activation via decreasing the energy barrier of *COOH dissociation to form *CO. The obtained key intermediate *CO is then bound to the Cu species for further reduction, leading to high selectivity toward methanol., (© 2021 Wiley-VCH GmbH.)

Guided by first-principles calculations, it was found that Cd single-atom catalysts (SACs) have excellent performance in activating CO 2 , and the introduction of axial coordination structure to Cd SACs cannot only further decrease the free energy barrier of CO 2 reduction, but also suppress the hydrogen evolution reaction (HER). Based on the above discovery, we designed and synthesized a novel Cd SAC that comprises an optimized CdN 4 S 1 moiety incorporated in a carbon matrix. It was shown that the catalyst exhibited outstanding performance in CO 2 electroreduction to CO. The faradaic efficiency (FE) of CO could reach up to 99.7 % with a current density of 182.2 mA cm -2 in a H-type electrolysis cell, and the turnover frequency (TOF) value could achieve 73000 h -1 , which was much higher than that reported to date. This work shows a successful example of how to design highly efficient catalysts guided by theoretical calculations., (© 2021 Wiley-VCH GmbH.)

A dual-site catalyst allows for a synergetic reaction in the close proximity to enhance catalysis. It is highly desirable to create dual-site interfaces in single-atom system to maximize the effect. Herein, we report a cation-deficient electrostatic anchorage route to fabricate an atomically dispersed platinum-titania catalyst (Pt 1 O1 /Ti 1-x O 2 ), which shows greatly enhanced hydrogen evolution activity, surpassing that of the commercial Pt/C catalyst in mass by a factor of 53.2. Operando techniques and density functional calculations reveal that Pt 1 O1 /Ti 1-x O 2 experiences a Pt-O dual-site catalytic pathway, where the inherent charge transfer within the dual sites encourages the jointly coupling protons and plays the key role during the Volmer-Tafel process. There is almost no decay in the activity of Pt 1 O1 /Ti 1-x O 2 over 300 000 cycles, meaning 30 times of enhancement in stability compared to the commercial Pt/C catalysts (10 000 cycles)., (© 2020 Wiley-VCH GmbH.)

Electroreduction of CO 2 to liquid fuels such as ethanol and n-propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen-doped graphene quantum dots (NGQ) on CuO-derived Cu nanorods (NGQ/Cu-nr) was an outstanding electrocatalyst for the reduction of CO 2 to ethanol and n-propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm -2 . This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu-nr could provide dual catalytic active sites and could stabilize the CH 2 CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu-nr had excellent synergistic effects for accelerating the reduction of CO 2 to alcohols., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Single-atom catalysts have attracted much attention. Reported herein is that regulating charge transfer of lattice oxygen atoms in serial single-atom-doped titania enables tunable hydrogen evolution reaction (HER) activity. First-principles calculations disclose that the activity of lattice oxygen for the HER can be regularly promoted by substituting its nearest metal atom, and doping-induced charge transfer plays an essential role. Besides, the realm of the charge transfer of the active site can be enlarged to the second nearest atom by creating oxygen vacancies, resulting in further optimization for the HER. Various single-atom-doped titania nanosheets were fabricated to validate the proposed model. Taking advantage of the localized charge transfer to the lattice atom is demonstrated to be feasible for realizing precise regulation of the electronic structures and thus catalytic activity of the nanosheets., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

For electrocatalysts for the hydrogen evolution reaction (HER), encapsulating transition metal phosphides (TMPs) into nitrogen-doped carbon materials has been known as an effective strategy to elevate the activity and stability. Yet still, it remains unclear how the TMPs work synergistically with the N-doped support, and which N configuration (pyridinic N, pyrrolic N, or graphitic N) contributes predominantly to the synergy. Here we present a HER electrocatalyst (denoted as MoP@NCHSs) comprising MoP nanoparticles encapsulated in N-doped carbon hollow spheres, which displays excellent activity and stability for HER in alkaline media. Results of experimental investigations and theoretical calculations indicate that the synergy between MoP and the pyridinic N can most effectively promote the HER in alkaline media., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Electrochemical reduction of CO 2 into energy-dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO 2 reduction. By using α-Co(OH) 2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h -1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4-times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO 2 to its radical anion (CO 2 .- ). Moreover, the more efficient stabilization of CO 2 .- intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α-Co(OH) 2 -supported atomic Ir electrocatalysts show enhanced CO 2 activity and stability., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Developing an efficient single-atom material (SAM) synthesis and exploring the energy-related catalytic reaction are important but still challenging. A polymerization-pyrolysis-evaporation (PPE) strategy was developed to synthesize N-doped porous carbon (NPC) with anchored atomically dispersed Fe-N 4 catalytic sites. This material was derived from predesigned bimetallic Zn/Fe polyphthalocyanine. Experiments and calculations demonstrate the formed Fe-N 4 site exhibits superior trifunctional electrocatalytic performance for oxygen reduction, oxygen evolution, and hydrogen evolution reactions. In overall water splitting and rechargeable Zn-air battery devices containing the Fe-N 4 SAs/NPC catalyst, it exhibits high efficiency and extraordinary stability. This current PPE method is a general strategy for preparing M SAs/NPC (M=Co, Ni, Mn), bringing new perspectives for designing various SAMs for catalytic application., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)