Hematite has been widely investigated for promising (photo)electrocatalysis due to its good robustness and abundant element content on earth, but its application in the electrochemical synthesis of ammonia is still plagued by unsatisfactory Faraday efficiency at ampere-scale current density. Herein, we prepared vertically aligned hematite nanosheet (denoted as Fe₂O₃-NS) arrays with a high-aspect-ratio (110) crystal facet exposed by applying a simple in situ electrochemical reconstruction strategy, which delivers unprecedentedly efficient ammonia yield of 189.05 mg h⁻¹ cm⁻² accompanied by faradaic efficiency of ca. 95% at a current density of exceeding 2.5 A cm⁻², outperforming the state-of-the-art Fe-based electrocatalysts. It is experimentally and theoretically revealed that the exposed (110) crystal plane of Fe₂O₃-NS is favorable for the adsorption and activation of intermediate species during electrocatalysis, and its vertically aligned nanosheet arrays provide abundant active sites and favorable charge transfer channels. The as-obtained hematite nanosheet arrays were finally employed as the cathode of a Zn–nitrate battery to deliver an outstanding discharge power density of 36.2 mW cm⁻².

中文翻译：

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垂直排列的赤铁矿纳米片，具有 （110） 个可控面，用于氨合成，法拉第效率超过 2.5 A cm−2


赤铁矿因其良好的稳健性和丰富的地球上元素含量而被广泛研究用于有前途的（光）电催化，但其在氨的电化学合成中的应用仍然受到安培级电流密度下不令人满意的法拉第效率的困扰。在此，我们通过应用简单的原位电化学重建策略制备了垂直排列的赤铁矿纳米片（表示为 Fe₂O_3-NS）阵列，该阵列具有高纵横比 （110） 晶体面，可提供前所未有的高效氨产率 189.05 mg ^{H-1 cm-2}，在电流密度超过 2.5 A ^{cm-2 时，法拉第效率约为 95%}，性能优于最先进的铁基电催化剂。实验和理论表明，Fe₂O_3-NS 的暴露 （110） 晶面有利于电催化过程中中间物质的吸附和活化，其垂直排列的纳米片阵列提供了丰富的活性位点和有利的电荷转移通道。所获得的赤铁矿纳米片阵列最终被用作 Zn-硝酸盐电池的阴极，以提供 36.2 mW ^cm-2 的出色放电功率密度。