Kim Kyeong-Ho, Kim Kyung-Hwan, Choi Wooseon, Kim Young-Min, Hong Seong-Hyeon, Choi Yun-Hyuk
Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 151-744, Republic of Korea.
School of Advanced Materials and Chemical Engineering, Daegu Catholic University, Gyeongsan 38430, Gyeongbuk, Republic of Korea.
Nanoscale. 2022 Jun 16;14(23):8281-8290. doi: 10.1039/d2nr01515c.
The electrocatalytic water splitting activity of V-based oxides has been rarely investigated, even though several polymorphs in VO are expected to exhibit different electrocatalytic activities depending on their crystal and electronic structures. The rutile structure of VO(R), showing metallic character, is a good candidate for a new electrocatalyst since it undergoes insulator-to-metal transition (IMT) from the insulating VO(M1) at a low temperature of 68 °C, and involves a substantially increased electrical conductivity by three orders of magnitude. The extensive improvements in the electrocatalytic activity for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) are confirmed when the IMT is induced where the overpotential () is reduced from 1056 mV to 598 mV in the OER and 411 mV to 136 mV in the HER, respectively. This improvement is attributed to the increased electrochemically active surface area (ECSA), reduced charge transfer resistance, and increased electron density, driven by the IMT to the metallic VO(R) phase.
尽管VO中的几种多晶型物预计会因其晶体和电子结构而表现出不同的电催化活性，但基于V的氧化物的电催化水分解活性却很少被研究。具有金属特性的VO(R)的金红石结构是一种新型电催化剂的良好候选者，因为它在68°C的低温下从绝缘的VO(M1)经历绝缘体-金属转变(IMT)，并且电导率大幅提高了三个数量级。当诱导IMT时，氧析出反应(OER)和析氢反应(HER)的电催化活性都有显著提高，其中OER的过电位(η)从1056 mV降至598 mV，HER的过电位从411 mV降至136 mV。这种改善归因于IMT驱动形成金属VO(R)相，导致电化学活性表面积(ECSA)增加、电荷转移电阻降低和电子密度增加。
