Understanding the fundamental properties, particularly identifying the independent effect of factors that govern catalytic activities, is crucial to design strategies for synthesizing efficient electrocatalysts. Here, we have explored the independent effect of mixed valence and oxygen defects on the catalytic origin by artificially engineering the stoichiometry of Li₂RuO₃. On the basis of the operando X-ray absorption spectroscopy (XAS) results, we demonstrated that the mixed valence enhanced the redox reversibility of ruthenium ions and the oxygen defects provided more electrocatalytic active sites. Consequently, non-stoichiometric Li_2−xRuO_3−y exhibited superior performance for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and Zn–air batteries in alkaline media compared to state-of-the-art Pt/C and RuO₂. Moreover, the applicability of the nonstoichiometric effect in various electrocatalytic reactions was systematically verified. Therefore, artificially induced non-stoichiometry is a feasible strategy to design efficient multifunctional electrocatalysts and this strategy can be applied to general metal oxide electrocatalysts for various electrocatalytic reactions.

中文翻译：

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探索人工诱导的Li2RuO3作为反应助催化剂的非化学计量效应对电催化行为的影响

了解基本特性，特别是确定控制催化活性的因素的独立作用，对于设计合成高效电催化剂的策略至关重要。在这里，我们通过人工设计Li ₂ RuO ₃的化学计量，探索了化合价和氧缺陷对催化起源的独立影响。基于操作X射线吸收光谱（XAS）结果，我们证明了混合价增强了钌离子的氧化还原可逆性，并且氧缺陷提供了更多的电催化活性位点。因此，非化学计量的Li ₂ - _x RuO _{3- y}与最新的Pt / C和RuO ₂相比，在碱性介质中对氧气还原反应（ORR），氧气析出反应（OER）和Zn-空气电池表现出优异的性能。此外，系统地验证了非化学计量效应在各种电催化反应中的适用性。因此，人工诱导的非化学计量是设计有效的多功能电催化剂的可行策略，并且该策略可以应用于用于各种电催化反应的通用金属氧化物电催化剂。