A lot of research has been going on to develop efficient nonprecious bifunctional catalysts for electrochemical water splitting. Here, we synthesize a V2O3-decorated spinel CoFe2O4 catalyst self-supported on nickel foam (NF) with a carbon-encapsulated mesoporous nanosheet structure [(V2O3–CoFe2O4)@C/NF] through a hydrothermal method and high-temperature annealing. It exhibits lower overpotentials for hydrogen evolution reaction (61 and 301 mV) and oxygen evolution reaction (226 and 310 mV) at ±10 and ±500 mA cm–2 and can hold at ±500 mA cm–2 for 80 h. As for overall water splitting, it needs 1.53 V to produce 10 mA cm–2 and maintains 80 h at 100 mA cm–2, suggesting good stability. This high performance originated from the V2O3-decorated spinel CoFe2O4, carbon-encapsulated structure and the self-supported mesoporous nanosheets. Therefore, this work provides a convenient, green, and promising method to design non-noble, low-cost, and high-efficient catalysts for water splitting.