Enhanced p–d Orbital Coupling in Unconventional Phase RhSb Alloy Nanoflowers for Efficient Ammonia Electrosynthesis in Neutral Media

Phase control provides a promising approach for physicochemical property modulation of metal/alloy nanomaterials toward various electrocatalytic applications. However, the controlled synthesis of alloy nanomaterials with unconventional phases remains challenging, especially for those containing both p- and d-block metals. Here, we report the one-pot synthesis of ultrathin RhSb alloy nanoflowers (NFs) with an unconventional 2H phase. Using 2H RhSb NFs as an electrocatalyst for nitrite reduction reaction in neutral media, the optimal NH₃ Faradaic efficiency and yield rate can reach up to 96.8% and 47.2 mg h⁻¹ mg_cat⁻¹ at −0.3 and −0.6 V (vs. reversible hydrogen electrode), respectively. With 2H RhSb NFs as a bifunctional cathode catalyst, the as-assembled zinc-nitrite/methanol batteries deliver a high energy efficiency of 96.4% and improved rechargeability with 120-h stable running. Ex/in situ characterizations and theoretical calculations have demonstrated that the phase change of RhSb from face-centered cubic (fcc) to 2H has optimized the electronic structure through stronger interactions between Rh and Sb by p–d orbital couplings, which improves the adsorption of key intermediates and reduces the reaction barriers of nitrite reduction to guarantee the efficient electrocatalysis. This work offers a feasible strategy of boosting the electrocatalytic performance of alloy nanostructures by integrating phase control and p–d orbital coupling.