Metastable Phase-Controlled Synthesis of Mesoporous Molybdenum Carbides for Efficient Alkaline Hydrogen Evolution

Transition metal carbides (TMCs) have shown great promise as nonprecious metal electrocatalysts for electrochemical energy conversion reactions owing to their Pt-like catalytic activity. The major challenges in the synthesis of TMCs include the selective formation of a catalytically active phase, enlargement of the catalytically active surface area, and control of the carbonaceous overlayer, all of which collectively influence their catalytic reactivity. Herein, we present a systematic study on the catalytically active metastable phase-selective synthesis of mesoporous molybdenum carbides with controlled carbon overlayer thickness for efficient alkaline hydrogen evolution reaction (HER) electrocatalysis. The synthesis of molybdenum carbides was explored by controlling the types of Mo and C precursors and carburization conditions and the use of a mesoporous silica template. The choice of …