Although Sn-based catalysts have recently achieved considerable improvement in selective electro-catalyzing CO₂ into HCOOH, the role of various valence Sn species is not fully understood due to the complexity and uncertainty of their evolution during the reaction process. Here, inspired by the theoretical simulations that the concomitant multivalent Sn (Sn⁰, Sn¹¹ and Sn^IV) can significantly motivate the intrinsic activity of Sn-based catalyst, the Sn/SnO/SnO₂ nanosheets were proposed to experimentally verify the synergistic effect of multivalent Sn species on the CO₂-into-HCOOH conversion. During CO₂ reduction reaction, the Sn/SnO/SnO₂ nanosheets, which are prepared by the sequential hydrothermal reaction, calcined crystallization and low-temperature H₂ treatment, exhibit a high FE_HCOOH of 89.6% at −0.9 V_RHE as well as a large cathodic current density. Systematic experimental and theoretical results corroborate that multivalent Sn species synergistically energize the CO₂ activation, the HCOO* adsorption, and the electron transfer, which make Sn/SnO/SnO₂ favour the conversion from CO₂ into HCOOH in both thermodynamics and kinetics. This proof-of-concept study establishes a relationship between the enhanced performance and the multivalent Sn species, and also provides a practicable and scalable avenue for rational engineering high-powered electrocatalysts.

尽管基于Sn的催化剂最近在选择性电催化将CO ₂转化为HCOOH方面已取得了很大的进步，但由于它们在反应过程中的发展非常复杂且不确定，因此各种价态Sn的作用尚未得到充分理解。在此，受理论模拟的启发，伴随的多价Sn（Sn ⁰，Sn ¹¹和Sn ^IV）可以显着激发Sn基催化剂的固有活性，提出了Sn / SnO / SnO ₂纳米片来实验验证协同效应。价锡物种对CO ₂转化为HCOOH的影响。在CO ₂还原反应中，Sn / SnO / SnO ₂通过顺序水热反应，煅烧结晶和低温H ₂处理制备的纳米片，在-0.9 V _RHE时表现出89.6％的高FE _HCOOH以及大的阴极电流密度。系统的实验和理论结果证实了多价Sn物种协同激发了CO ₂活化，HCOO *吸附和电子转移，从而使Sn / SnO / SnO ₂有利于从CO ₂转化。在热力学和动力学上都转化为HCOOH。这项概念验证研究建立了性能增强与多价锡物种之间的关系，并且为合理设计高性能电催化剂提供了可行且可扩展的途径。