Synergistic Effect of a Bi ₂ MoO ₆ /g-C ₃ N ₄ Composite for Highly Selective Electrocatalytic Oxygen Reduction to Produce H ₂ O ₂

The design of high-performance electrocatalysts for the environmentally friendly synthesis of hydrogen peroxide (H 2 O 2 ) via a two-electron oxygen reduction reaction (2e – ORR) method, which presents a promising alternative to the traditional anthraquinone process, remains a significant challenge. Thus, there is an urgent demand for the development of highly efficient and selective electrocatalysts for H 2 O 2 generation. Herein, a cost-effective, precious metal-free Aurivillius oxide and heteroatom-based carbon composite material, i.e., Bi 2 MoO 6 /g-C 3 N 4 (BMO/gCN), synthesized by the solvothermal method, is demonstrated for the 2e – ORR. The optimized composite catalyst (1:1 BMO/gCN) exhibits superior H 2 O 2 selectivity of 86–97% at a wide potential range of 0.2–0.6 V versus RHE and electron transfer number ( n ) values between 2.06 and 2.27 in 0.1 M KOH electrolyte. The synthesized electrocatalyst exhibits consistent H 2 O 2 selectivity, as demonstrated by a 50 h durability test at 0.3 V versus RHE. The Faradaic efficiency and H 2 O 2 yield rate reached a maximum of 98% and 860 mmol g –1 h –1, respectively, at 0.3 V versus RHE after 5 h of electrocatalysis for H 2 O 2 production. To further support the experimental finding, density functional theory calculations using the Perdew–Burke–Ernzerhof functional with Grimme’s D3 dispersion correction are performed. The BMO/gCN composite structure exhibits the favorable Gibbs free energy profile for the 2e – ORR pathway, with spontaneous OOH* formation (Δ G = −1.00 eV) and highly exothermic H 2 O 2 generation (Δ G = −1.28 eV), confirming its superior catalytic activity and selectivity toward H 2 O 2 production. This work presents a fresh approach to an efficient electrocatalyst for 2e – ORR.