College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, 401331, China.
Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China.
Adv Mater. 2023 May;35(21):e2300027. doi: 10.1002/adma.202300027. Epub 2023 Apr 2.
Piezo-electrocatalysis as an emerging mechano-to-chemistry energy conversion technique opens multiple innovative opportunities and draws great interest over the past decade. However, the two potential mechanisms in piezo-electrocatalysis, i.e., screening charge effect and energy band theory, generally coexist in the most piezoelectrics, making the essential mechanism remain controversial. Here, for the first time, the two mechanisms in piezo-electrocatalytic CO reduction reaction (PECRR) is distinguished through a narrow-bandgap piezo-electrocatalyst strategy using MoS nanoflakes as demo. With conduction band of -0.12 eV, the MoS nanoflakes are unsatisfied for CO -to-CO redox potential of -0.53 eV, yet they achieve an ultrahigh CO yield of ≈543.1 µmol g h in PECRR. Potential band position shifts under vibration are still unsatisfied with CO -to-CO potential verified by theoretical investigation and piezo-photocatalytic experiment, further indicating that the mechanism of piezo-electrocatalysis is independent of band position. Besides, MoS nanoflakes exhibit unexpected intense "breathing" effect under vibration and enable the naked-eye-visible inhalation of CO gas, independently achieving the complete carbon cycle chain from CO capture to conversion. The CO inhalation and conversion processes in PECRR are revealed by a self-designed in situ reaction cell. This work brings new insights into the essential mechanism and surface reaction evolution of piezo-electrocatalysis.
压电电化学催化作为一种新兴的机械化学能量转换技术，在过去十年中引起了广泛关注，并开辟了许多创新机会。然而，压电电化学催化中存在两种潜在的机制，即屏蔽电荷效应和能带理论，这两种机制通常同时存在于大多数压电体中，使得其基本机制仍存在争议。在这里，首次通过使用 MoS 纳米片作为演示材料的窄带隙压电催化剂策略，区分了压电电化学催化 CO 还原反应 (PECRR) 中的这两种机制。具有 -0.12 eV 导带的 MoS 纳米片对于 CO 到 CO 氧化还原电位 -0.53 eV 来说并不满意，但它们在 PECRR 中实现了超高的 CO 产率≈543.1 µmol g h。振动下的势能带位置移动仍然不能满足 CO 到 CO 电位的要求，这通过理论研究和压电光催化实验得到了验证，进一步表明压电催化的机制与能带位置无关。此外，MoS 纳米片在振动下表现出出人意料的强烈“呼吸”效应，并使肉眼可见的 CO 气体被吸入，独立地实现了从 CO 捕获到转化的完整碳循环链。通过自行设计的原位反应池揭示了 PECRR 中的 CO 吸入和转化过程。这项工作为压电电化学催化的基本机制和表面反应演化提供了新的见解。
