Begildayeva Talshyn, Theerthagiri Jayaraman, Lee Seung Jun, Yu Yiseul, Choi Myong Yong
Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences, Gyeongsang National University, Jinju, 52828, South Korea.
Core-Facility Center for Photochemistry & Nanomaterials, Gyeongsang National University, Jinju, 52828, South Korea.
Small. 2022 Nov;18(47):e2204309. doi: 10.1002/smll.202204309. Epub 2022 Oct 3.
Herein, the authors produce Co-based (Co (PO ) , Co O , and Co S ) electrocatalysts via pulsed laser ablation in liquid (PLAL) to explore the synergy of anion modulation on phase-selective active sites in the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Co (PO ) displays an ultralow overpotential of 230 mV at 10 mA cm with 48.5 mV dec Tafel slope that outperforms the state-of-the-art Ir/C in OER due to its high intrinsic activity. Meanwhile, Co S exhibits the highest HER performance known to the authors among the synthesized Co-based catalysts, showing the lowest overpotential of 361 mV at 10 mA cm with 95.8 mV dec Tafel slope in the alkaline medium and producing H gas with ≈500 mmol g h yield rate under -0.45 V versus RHE. The identified surface reactive intermediates over in situ electrochemical-Raman spectroscopy reveal that cobalt(hydr)oxides with higher oxidation states of Co-cation forming under oxidizing potentials on the electrode-electrolyte surface of Co (PO ) facilitate the OER, while Co(OH) facilitate the HER. Notably, the fabricated two-electrode electrolyzers using Co (PO ) , Co O , and Co S electrocatalysts deliver the cell potentials ≈2.01, 2.11, and 1.89 V, respectively, at 10 mA cm . This work not only shows PLAL-synthesized electrocatalysts as promising candidates for water splitting, but also provides an underlying principle for advanced energy-conversion catalysts and beyond.
在此，作者通过液体脉冲激光烧蚀（PLAL）制备了钴基（Co(PO₄)₃、Co₃O₄和CoS₂）电催化剂，以探索阴离子调制对电催化析氢反应（HER）和析氧反应（OER）中相选择性活性位点的协同作用。Co(PO₄)₃在10 mA cm⁻²时表现出230 mV的超低过电位，Tafel斜率为48.5 mV dec⁻¹，由于其高本征活性，在OER中优于目前最先进的Ir/C。同时，CoS₂在合成的钴基催化剂中表现出作者所知的最高HER性能，在碱性介质中，在10 mA cm⁻²时表现出361 mV的最低过电位，Tafel斜率为95.8 mV dec⁻¹，在相对于可逆氢电极（RHE）为-0.45 V的条件下，产氢速率约为500 mmol g⁻¹ h⁻¹。原位电化学拉曼光谱确定的表面反应中间体表明，在Co(PO₄)₃的电极-电解质表面，在氧化电位下形成的具有较高氧化态Co阳离子的钴（氢）氧化物促进OER，而Co(OH)₂促进HER。值得注意的是，使用Co(PO₄)₃、Co₃O₄和CoS₂电催化剂制造的两电极电解槽在10 mA cm⁻²时的电池电位分别约为2.01、2.11和1.89 V。这项工作不仅表明PLAL合成的电催化剂是水分解的有前途的候选材料，而且为先进的能量转换催化剂及其他领域提供了一个基本原理。
