Ultrafast Thermal Synthesis of Non-Noble Metal-Based Electrocatalysts for Overall Water Splitting

Non-noble metal-based electrocatalysts have attracted extensive interest due to their low-cost, earth-abundance, and highly efficient catalytic performance as alternatives to noble metal counterparts. However, conventional approaches to synthesize electrocatalysts can endure overlong synthesis time with throughput degradation. Here, we demonstrate an ultrafast thermal method to synthesize non-noble metal-based electrocatalysts for overall water splitting. The method can be extensively used for metal-based catalysts, including metal oxides, metal carbides, alloys, and their composites. Among them, we select two outstanding electrocatalysts as examples for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The hybrid structure of nickel oxides and molybdenum carbides on activated carbon felt (Ni–Mo@ACF) for HER shows remarkable catalytic activity with a low overpotential of 87 mV and an excellent durability for 48 h at a current density of 10 mA cm–2. The NiFe alloy nanosheets on activated carbon felt (NiFe@ACF) for OER show superb catalytic activity with a low overpotential of 270 mV and great durability for 48 h at a current density of 10 mA cm–2. Consequently, an overall water splitter assembled with Ni–Mo@ACF as the cathode and NiFe@ACF as the anode only requires a low cell voltage of 1.60 V to drive a current density of 10 mA cm–2 with excellent durability for 36 h, which is the best among non-noble metal-based electrocatalysts reported so far. This work offers an approach for the ultrafast and facile synthesis of non-noble metal-based electrocatalysts for water splitting and other applications.