Electrocatalytic water splitting driven by renewable energy input to produce clean H₂ has been widely viewed as a promising strategy of the future energy portfolio. Currently, the state-of-the-art electrocatalysts for water splitting in acidic solutions are IrO₂ or RuO₂ for the O₂ evolution reaction (OER) and Pt for the H₂ evolution reaction (HER). Realization of large-scale H₂ production from water splitting requires competent nonprecious electrocatalysts. Despite the advances of decades in this field, several challenges still exist and need to be overcome: (1) Most efforts in the design of nonprecious electrocatalysts have focused on developing HER catalysts for acidic conditions but OER catalysts for alkaline conditions owing to their thermodynamic convenience, potentially resulting in incompatible integration of the two types of catalysts and thus inferior overall performance. (2) In conventional water electrolysis, HER and OER are strictly coupled and therefore H₂ and O₂ are produced simultaneously, which may lead to explosive H₂/O₂ mixing due to gas crossover. Meanwhile, the coexistence of H₂, O₂, and electrocatalysts could produce reactive oxygen species that might shorten the lifetime of an electrolyzer. (3) The HER rate is often limited by that of OER due to the more sluggish kinetics of the latter, which lowers the overall energy conversion efficiency. Moreover, the product of OER, O₂, is not highly valuable. (4) It remains challenging to develop efficient and low-cost H₂ storage and transport systems for the future H₂ economy.

中文翻译：

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电催化水分解的创新策略

由可再生能源输入驱动产生清洁H _2的电催化水分解已被广泛视为未来能源组合中的一项有前途的策略。当前，用于在酸性溶液中进行水分解的最先进的电催化剂是用于O ₂析出反应（OER）的IrO ₂或RuO ₂以及用于H ₂析出反应（HER）的Pt 。大规模H _2的实现由水分解产生的产物需要合格的非贵金属电催化剂。尽管该领域已经取得了数十年的进步，但仍然存在一些挑战，需要克服：（1）非贵重电催化剂设计中的大多数努力都集中在开发用于酸性条件的HER催化剂，但由于其热力学上的方便性而用于碱性条件的OER催化剂。 ，可能导致两种催化剂的不相容结合，从而降低整体性能。（2）在常规的水电解中，HER和OER严格耦合，因此同时产生H ₂和O ₂，这可能由于气体交叉而导致爆炸性的H ₂ / O ₂混合。同时，H并存₂，O ₂和电催化剂可能会产生活性氧，可能会缩短电解器的寿命。（3）HER速率通常受OER速率的限制，因为后者的动力学更为缓慢，这降低了整体能量转换效率。此外，OER的产物O _2的价值不高。（4）为未来的H ₂经济开发高效，低成本的H ₂储存和运输系统仍然具有挑战性。