Electrocatalytic hydrogen evolution and sulfion (S²⁻) recycling are promising strategies for boosting H₂ production and removing environmental pollutants. Here, a nano-Ni-functionalized molybdenum disulfide (MoS₂) nanosheet was assembled on steel mesh (Ni-MoS₂/SM) for use in sulfide oxidation reaction-assisted, energy-saving H₂ production. Experimental and theoretical calculation results revealed that anchoring nano-Ni on high-surface-area slack MoS₂ nanosheets not only optimized catalyst adsorption of polysulfides but also played an important role in promoting hydrogen evolution reaction kinetics by absorbing OH_ad, thereby greatly enhancing the catalytic performance toward sulfide oxidation reaction and hydrogen evolution reaction. Meanwhile, the Ni/MoS₂-based hydrogen evolution reaction + sulfide oxidation reaction system achieved nearly 100% hydrogen production efficiency and only consumed 61% less power per kWh than the oxygen evolution reaction + hydrogen evolution reaction system, which suggested our proposed Ni-MoS₂ and novel hydrogen production system are promising for sustainable energy production.