Engineering Surface Wettability of Ceramic Carbon Electrode for Improved Hydrogen Evolution Performance of Molybdenum Sulfide Electrocatalyst
In the present work, we explored an economically-feasible and environmentally friendly attempt to achieve tunable wettability of ceramic carbon substrates applicable in water splitting devices. It was found that by rationally controlling the surface functional groups, ceramic carbon substrate with difference surface hydrophilicity, electroactive surface area, and electrochemical behavior could be achieved. Particularly, hydrophilic ceramic carbon electrode (CCE) was obtained by using tetramethoxysilane as the modifier, which allows uniform anchoring of amorphous molybdenum sulfide (MoSx) hydrogen evolution electrocatalyst on their surface through a simple chemical vapor deposition method. The optimized CCE/MoSx exhibited promising hydrogen evolution reaction activity and good stability, with a small onset overpotential (~250 mV) and a low Tafel slope (58 mV/dec). The CCE/MoSx catalyst also shows reasonable stability for under acidic conditions. Such promising electrochemical performance has been attributed to the strong chemical and electronic coupling between the conducting CCE and the MoSx. This work paves a new way for rational design and fabrication of efficient composite electrode through selecting ceramic carbon as a durable high-conductivity substrate, and the collaborative optimization of the catalyst and the substrate to achieve higher hydrogen evolution performance.