For steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO2 reduction reaction and provided a platform for rational material design. C2+ product selectivity could be additionally improved by doping p-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C2H4 at −0.55 V (vs RHE) and a C2H4 cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C2+ selectivity of 82.3% at a partial current density of 329.2 mA/cm2 was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO2-to-C2H4 conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion.

Cu acetate/PAN nanofibers were transformed into porous C nanofibers with doped N and Cu particles, via O2 partial pressure-controlled calcination. N atoms next to Cu trigger the CO2RR by increasing the amount of CO* on the Cu, lowering the energy needed for CO dimerization.

The effect of local atomic arrangement of CuZn alloys was demonstrated on enhanced ethanol selectivity from CO2RR and supported by density functional theory (DFT) calculations.

Molybdenum disulfide (MoS2) has attracted much attention as a material to replace the noble-metal-based hydrogen evolution reaction catalyst. Polymorphism is an important factor in improving the catalytic performance of transition-metal dichalcogenides (TMDs) including MoS2. Several methods have been proposed to synthesize the 1T/1T′ phase with high catalytic efficiency, and a gas–solid reaction has recently been proposed as one of the alternative methods. However, the atomic-scale reaction mechanism between gas molecules and MoS2 has not been clarified. Here, we report a detailed atomic-scale mechanism of structural phase transition of MoS2 nanocrystals under reaction with CO gas molecules using density functional theory calculations. We confirm that the evaporation of S atoms at the edge is much faster than the evaporation at the basal plane of MoS2 nanocrystals. It is found that the S evaporation at the edge induces the structural change from 2H to 1T/1T′ in the basal plane of nanocrystals. The structural change is also attributed to the chain reaction due to the sequential migration of S atoms to the octahedral sites, which is energetically favorable. The present results provide a guideline for the gas–solid reaction-based phase control of TMDs including MoS2 to synthesize a high-performance catalyst.