Renewable energy-based electrocatalytic oxidation for hydrogen production in complex reaction environments such as industrial wastewater and human urine demands high-performing catalysts to conduct switchable urea oxidation reactions (UOR) and traditional oxygen evolution reactions (OER). Here, a novel bifunctional nanosheet electrocatalyst is reported, Ir-Ni₃N, which exhibits excellent electrocatalytic activity for both OER and UOR under alkaline conditions. Specifically, the overpotentials at 100 mA cm^-2 for OER and UOR are 1.59 and 1.37 V vs. reversible hydrogen electrode (RHE) respectively, which are superior to most of the recently reported nickel-based catalysts. Accordingly, a comprehensive mechanism for competitive catalytic activities of Ni and Ir sites in Ir-Ni₃N and the switch between OER and UOR that guarantees consistent hydrogen production is proposed. This study provides a feasible strategy for continuous hydrogen production aided by reagent-adaptive electrocatalysts in urea-containing wastewater.