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.