Influence of Carbon on Molybdenum Carbide Catalysts for the Hydrogen Evolution Reaction

Phosphorus-decorated Mo-MXene/CQD hybrid: a 2D/0D architecture for bifunctional electrochemical water splitting

The exploration of nonprecious metal-based 2D bifunctional electrocatalysts is of great significance for transforming to sustainable energies in terms of hydrogen. However, to achieve commendable electrocatalytic performance via rational design of surface-interface-engineered Mo-MXene hybrids remain challenging and highly demanding. Herein, we report large size exfoliated Mo-MXene sheets, which provide a flat flexible interface for decoration with carbon quantum dots (CQDs) and controlled surface phosphorization (denoted as Mo-MX/C/P hybrid). The resulting Mo-MX/C/P hybrid exhibited the lowest onset potentials of 14 and 58 mV at an applied current of 0.2 mA cm^-2 for the HER and OER, respectively. Strikingly, the electronegative nature of phosphorous (P) and quick charge transfer between the CQDs and Mo₂CTx matrix were responsible for its superior catalytic activities. Despite the superior performance, the Mo-MX/C/P hybrid can also be used for full-cell division of water with a cell voltage of 1.34 volts at 10 mA cm^-2 and was found to be durable up to 12. This work provides a novel insight into the further development of surface-interface-engineered Mo-MXene hybrids for sustainable energy.

3D self-assembly of ultrafine molybdenum carbide confined in N-doped carbon nanosheets for efficient hydrogen production

Electrochemical water splitting has been intensively pursued as a promising approach to produce clean and sustainable hydrogen fuel. However, the lack of low-cost and high-performance electrocatalysts for the hydrogen evolution reaction (HER) hinders the large-scale application. Herein, we have rationally designed and synthesized 3D self-assembly architectures assembled from ultrafine MoC nanoparticles (0D) uniformly embedded within N-doped carbon nanosheets (2D) for the HER via a simple protocol. The well-organized 3D nanostructures are composed of very small MoC nanocrystallites (<2 nm) and free-stretching conductive carbon nanosheets with high specific surface areas and abundant mesopores, which can expose more active sites and facilitate electron/ion transport pathways. Based on the merits of the composition and configuration, the resultant hierarchical 3D self-assembly architectures exhibit remarkable electrocatalytic performance and stability for the HER.