Tanglue Feng,Jingkun Yu,Da Yue,Haoqiang Song,Songyuan Tao,Geoffrey I.N. Waterhouse,Siyu Lu,Bai Yang
Designing highly active and durable electrocatalysts for oxygen evolution reaction (OER) over a wide pH range is of great significance, but it remains challenging. Herein, a defect-rich RuO 2 electrocatalyst with pH-universal OER activity is developed by rationally utilizing the electronic reservoir effect of Mn-coordinated carbonized polymer dots (Mn-CPDs). Mn-CPDs as distinct electron acceptor/donor endows Ru-O sites of RuO 2 with abundant defective structures (i.e., O-Ru-O-Ru-Ru sites and O-Ru-O-Mn units) via reduction-oxidation processes, with incorporated Mn atoms simultaneously feeding electron to Ru. The resultant Ru-O-Mn/CPD exhibits an ultralow OER potential of 196 mV, 194 mV and 251 mV at 10 mA·cm −2 under 0.5 M H 2 SO 4 , 1.0 M KOH, and 1.0 M PBS media, respectively, and long-term catalytic stability, which are among the best OER electrocatalysts. Surprisingly, Ru-O-Mn/CPD also shows great Pt-like hydrogen evolution activity. The theoretical simulation indicates that defective Ru-O-Mn structures produce electron-rich Ru region and near-optimal Ru-4d/O-2p band center, thus optimizing the adsorption/desorption kinetics of key intermediates.
Jie Huang,Yeqing Chen,Pengpeng Rao,Zongming Ni,Xueying Chen,Jie Zhu,Chen Li,Gaoyang Xiong,Ping Liang,Xin He,Songnan Qu,Jun Lin
Carbonized polymer dots (CPDs) have received tremendous attention during the last decade due to their excellent fluorescent properties and catalytic performance. Doping CPDs with transition metal atoms accelerates the local electron flow in CPDs and improves the fluorescent properties and catalytic performance of the CPDs. However, the binding sites and the formation mechanisms of the transition-metal-atom-doped CPDs remain inconclusive. In this work, Mn 2+ -ion–doped CPDs (Mn-CPDs) are synthesized by the hydrothermal method. The Mn 2+ ions form Mn O bonds that bridge the sp 2 domains of carbon cores and increases the effective sp 2 domains in the Mn-CPDs, which redshifts the fluorescence emission peak of the Mn-CPDs slightly. The Mn 2+ ions form covalent bonds in the CPDs and remedy the oxygen vacancies of the CPDs, which cuts off the non-radiative–recombination process of the Mn-CPDs and increases the quantum yield of the Mn-CPDs to 70%. Furthermore, the Mn O bonds accelerate the electron flow between adjacent sp 2 domains and enhances the electron transport in the Mn-CPDs. Thus, the Mn-CPDs demonstrate excellent catalytic performance to activate hydrogen peroxide (H 2 O 2 ) and produce hydroxyl radicals (•OH) to degrade methylene blue (MB) and rhodamine B (RhB).
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