Interfacial engineering and hydrophilic/aerophobic tuning of Sn4P3/Co2P heterojunction nanoarrays for high-efficiency fully reversible water electrolysis

The simultaneous integration of electronic regulation and architectural engineering in one electrocatalyst represents a powerful leverage to concurrently boost the electrocatalytic performance towards overall water splitting. We herein rationally fabricate Sn4P(3)/Co2P "stalk "- "cap "-typed nanoarrays (Sn4P(3)/Co2P SCNAs) with abundant heterointerfaces and elaborately implanted "caps ". The nanoarrayed structure can substantially enlarge the exposure of active sites and promote the mass/electron transport, thus accelerating the reaction kinetics. Moreover, the purposely grafted "caps " are beneficial to increase the hydrophilicity/aerophobicity, which facilitate the water affinity and release of generated gas bubbles. Accordingly, the obtained Sn4P3/Co2P SCNAs deliver exceptional electrocatalytic performances towards the HER and OER, as reflected by the over potentials of 45.4 and 280.4 mV at 10 mA cm(-2), respectively. More impressively, the two-electrode electrolyzer assembled by freestanding Sn4P(3)/Co2P SCNAs requires a cell voltage of 1.56 V at 10 mA cm(-2) and exhibits superior stability and full reversibility, holding great potential in practical water electrolysis.