Developing low-cost electrocatalysts to replace precious Ir-based materials is key for oxygen evolution reaction (OER). Here, we report atomically dispersed nickel coordinated with nitrogen and sulfur species in porous carbon nanosheets as an electrocatalyst exhibiting excellent activity and durability for OER with a low overpotential of 1.51 V at 10 mA cm −2 and a small Tafel slope of 45 mV dec −1 in alkaline media. Such electrocatalyst represents the best among all reported transition metal- and/or heteroatom-doped carbon electrocatalysts and is even superior to benchmark Ir/C. Theoretical and experimental results demonstrate that the well-dispersed molecular S|NiN x species act as active sites for catalyzing OER. The atomic structure of S|NiN x centers in the carbon matrix is clearly disclosed by aberration-corrected scanning transmission electron microscopy and synchrotron radiation X-ray absorption spectroscopy together with computational simulations. An integrated photoanode of nanocarbon on a Fe 2 O 3 nanosheet array enables highly active solar-driven oxygen production.

Atomically dispersed Ni–Nx species anchored porous carbon matrix with embedded Ni nanoparticles was synthesized for highly efficient hydrogen evolution in alkaline conditions.

Designing nonprecious electrocatalysts with multiple active sites and prolonged durability in an integrated electrolyte toward water splitting is momentous for renewable energies being reserved in chemical fuels. Herein, we developed a method for synthesizing multimetallic hydroxide nanosheets by corroding nickel foam with chloride ions, which enabled the screening and discovery of various multimetallic hydroxide electrocatalysts toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). We discovered that Ni5Co3Mo–OH nanosheets exhibited electrocatalytic performances toward OER (η100 = 304  mV) and HER (η10 = 52  mV). Moreover, Ni5Co3Mo–OH can be employed as active bifunctional catalysts toward overall water splitting with a low cell voltage of 1.43 V at 10 mA·cm–2 (1.60 V at 100 mA·cm–2) and stable operation for 100 h (100 mA·cm–2). This work provides a method to develop multimetallic hydroxides for electrocatalysis and energy conversion.

Regulating the local environment and structure of metal center coordinated by nitrogen ligands (M‐N4) to accelerate overall reaction dynamics of the electrochemical CO2 reduction reaction (CO2RR) has attracted extensive attention. Herein, we develop an axial traction strategy to optimize the electronic structure of the M‐N4 moiety and construct atomically dispersed nickel sites coordinated with four nitrogen atoms and one axial oxygen atom, which are embedded within the carbon matrix (Ni‐N4‐O/C). The Ni‐N4‐O/C electrocatalyst exhibited excellent CO2RR performance with a maximum CO Faradic efficiency (FE) close to 100 % at −0.9 V. The CO FE could be maintained above 90 % in a wide range of potential window from −0.5 to −1.1 V. The superior CO2RR activity is due to the Ni‐N4‐O active moiety composed of a Ni‐N4 site with an additional oxygen atom that induces an axial traction effect.

Dual‐atom catalysts have the potential to outperform the well‐established single‐atom catalysts for the electrochemical conversion of CO2. However, the lack of understanding regarding the mechanism of this enhanced catalytic process prevents the rational design of high‐performance catalysts. Herein, an obvious synergistic effect in atomically dispersed Ni–Zn bimetal sites is observed. In situ characterization combined with density functional theory (DFT) calculations reveals that heteronuclear coordination modifies the d‐states of the metal atom, narrowing the gap between the d‐band centre (εd) of the Ni (3d) orbitals and the Fermi energy level (EF) to strengthen the electronic interaction at the reaction interface, resulting in a lower free energy barrier (ΔG) in the thermodynamic pathway and a reduced activation energy (Ea) as well as fortified metal–C bonding in the kinetic pathway. Consequently, a CO faradaic efficiency of >90% is obtained across a broad potential window from −0.5 to −1.0 V (vs RHE), reaching a maximum of 99% at −0.8 V, superior to that of the Ni/Zn single‐metal sites.

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Emerging single‐atom catalysts (SACs) hold great promise for CO2 electroreduction (CO2ER), but the design of highly active and cost‐efficient SACs is still challenging. Herein, a gas diffusion strategy, along with one‐step thermal activation, for fabricating N‐doped porous carbon polyhedrons with trace isolated Fe atoms (Fe1NC) is developed. The optimized Fe1NC/S1‐1000 with atomic Fe‐N3 sites supported by N‐doped graphitic carbons exhibits superior CO2ER performance with the CO Faradaic efficiency up to 96% at −0.5 V, turnover frequency of 2225 h−1, and outstanding stability, outperforming almost all previously reported SACs based on N‐doped carbon supported nonprecious metals. The observed excellent CO2ER performance is attributed to the greatly enhanced accessibility and intrinsic activity of active centers due to the increased electrochemical surface area through size modulation and the redistribution of doped N species by thermal activation. Experimental observations and theoretical calculations reveal that the Fe‐N3 sites possess balanced adsorption energies of *COOH and *CO intermediates, facilitating CO formation. A universal gas diffusion strategy is used to exclusively yield a series of dimension‐controlled carbon‐supported SACs with single Fe atoms while a rechargeable Zn–CO2 battery with Fe1NC/S1‐1000 as cathode is developed to deliver a maximal power density of 0.6 mW cm−2.

Electrocatalysts playak ey role in accelerating the sluggish electrochemical CO 2 reduction (ECR) involving multi-electron and proton transfer.W en ow develop ap roton capture strategy by accelerating the water dissociation reaction catalyzedb yt ransition-metal nanoparticles (NPs) adjacent to atomically dispersed and nitrogen-coordinated single nickel (NiÀN x )a ctive sites to accelerate proton transfer to the latter for boosting the intermediate protonation step,a nd thus the whole ECR process.A berration-corrected scanning transmission electron microscopy, X-ray absorption spectroscopy, and calculations reveal that the Ni NPs accelerate the adsorbed H (H ad )g eneration and transfer to the adjacent Ni À N x sites for boosting the intermediate protonation and the overall ECR processes.T his proton capture strategy is universal to design and prepare for various high-performance catalysts for diverse electrochemical reactions even beyond ECR.