Supports promote single-atom catalysts toward advanced electrocatalysis

Developing low‐cost and high‐efficiency catalysts for sustainable hydrogen production through electrocatalytic hydrogen evolution reaction (HER) is crucial yet remains challenging. Here, a strategy is proposed to fill Ni‐vacancy (Niv) sites of dual‐deficient NiO (D‐NiO‐Pt) deliberately created by Ar plasma with homogeneously distributed Pt atoms driven by oxygen vacancies (Ov). The incorporated Pt atoms filling the Niv reduce the formation energy to increase crystal stability, and subsequently combine with additional Ov to tune the electronic structure of the surrounding Ni sites. Thus, a more ideal hydrogen adsorption free energy (ΔGH*) closer to 0 of Ni sites and Pt sites can be achieved. As a result, the D‐NiO‐Pt electrode achieves superior mass activity of ≈1600 mA mg−1 (normalized by platinum) and nearly negligible loss of activity during long‐term operation, which is much better than as‐prepared Pt‐containing NiO catalysts without plasma treatment. A low overpotential of 20 mV is required for the D‐NiO‐Pt at 10 mA cm−2 in alkaline HER, outperforming that of the commercial Pt/C. In addition, the universal access to the other Ni‐based compounds including nickel phosphide (Ni2P), nickel sulfide (Ni0.96S), and nickel selenide (NiSe2) is also demonstrated by employing a vacancy‐driven Pt filling mechanism.

Atomic‐Level Platinum Filling into Ni‐Vacancies of Dual‐Deficient NiO for Boosting Electrocatalytic Hydrogen Evolution

Polycrystalline SnSx nanofilm enables CO2 electroreduction to formate with high current density.

Race on engineering noble metal single-atom electrocatalysts for water splitting

The design of a highly efficient and durable electrocatalyst for the production of hydrogen via electrochemical water splitting is highly desirable but remains a tremendous challenge. Though there has been some progress in basic media wherein the reaction is sluggish, here we report the synthesis of a new hybrid catalyst comprising Cu and Rh elements as bimetallic single atoms (SAs) and nanoparticles (NPs) on a N-doped graphene (GN) surface (1: Cu/Rh(SAs) + Cu2Rh(NPs)/GN) that works remarkably fast for the hydrogen evolution reaction (HER) in acidic media. Benefiting from the large specific electrochemical surface area, low charge transfer resistance and combined synergistic effect of bimetallic SAs and NPs, the as-obtained catalyst 1 requires an overpotential as low as 8 mV (commercial Pt/C requires 14 mV) in 0.5 M H2SO4 solution to deliver a benchmark current density of 10 mA cm−2. It maintains constant current densities (∼10–100 mA cm−2) at both low and high overpotentials during the 500 h continuous HER electrolysis chronoamperometry test. Moreover, 1 exhibits a low Tafel slope (27 mV dec−1), a high turnover frequency and mass activity (1.237 s−1 and 2.314 A mgRh−1) which are higher than those of Pt/C (0.329 s−1 and 0.326 A mgPt−1) and a constant H2 production rate with high faradaic efficiency (98–99%). Electrochemical experiments in conjunction with density functional theory (DFT) calculations reveal that the combination of Rh and Cu atoms on the GN surface not only maximizes the rates of H+ adsorption on the electrode surface (due to the high surface area of 1) but also optimizes the hydrogen adsorption free energy (ΔGH*) close to zero (0.01 eV), improving the intrinsic catalytic activity for the HER.

Hansaem Choi

Papers

Modulation of Cu and Rh single-atoms and nanoparticles for high-performance hydrogen evolution activity in acidic media

Design of less than 1 nm Scale Spaces on SnO2 Nanoparticles for High-Performance Electrochemical CO2 Reduction

Local pH induced electrochemical CO2 reduction on nanostructured Ag for adjustable syngas composition

Compensating the impurities on the Cu surface by MOFs for enhanced hydrocarbon production in the electrochemical reduction of carbon dioxide