Pengqi Zhu,Mengting Gao,Jin Zhang,Zhiwei Wu,Ruiyi Wang,Yunwei Wang,Eric R. Waclawik,Zhanfeng Zheng
Coordinated Ru species, Ru/LDH, were applied to the reduction of carbonyl compounds via blue light irradiation under mild (45 °C, atmospheric argon pressure), ligand-free, and additive-free conditions. LDH can act as an efficient base catalyst to assist in formation of isopropoxide, requiring no additional base, because basic OH groups form an ordered distribution on LDH surface. The coordinated Ru species containing one OH and three oxygen atoms ligands deriving from the OH groups of LDH are a crucial component, for securing the active electron-deficient Ru species that favours formation of Ru-isopropoxide. The photocatalytic activity is related to the adsorption capacity of isopropyl alcohol near the electron-deficient Ru species and the formation of Ru-isopropoxide. The strong-metal-support interactions between Ru and LDH affect the coordination and the electronic surroundings of the Ru centres and have a significant effect on the photocatalytic activity.
Electrochemical nitrate reduction reaction offers a sustainable and efficient pathway for ammonia synthesis. Maintaining satisfactory Faradaic efficiency for long-term nitrate reduction under ampere-level current density remains challenging due to the inevitable hydrogen evolution, particularly in pure nitrate solutions. Herein, we present the application of electron deficiency of Ru metals to boost the repelling effect of counter K + ions via the electric-field-dependent synergy of interfacial water and cations, and thus largely promote nitrate reduction reaction with a high yield and well-maintained Faradaic efficiency under ampere-level current density. The pronounced electron deficiency of Ru metals boosts the repelling effect on hydrated K + ions, as indicated by the distance of K + ions to catalyst surface, which can loosen the water layer to depress hydrogen evolution and accelerate nitrate conversion. Consequently, the optimized electrode loaded with electron-deficient Ru atomic layers can directly produce 0.26 M ammonia solution in pure nitrate solution in 6 h, providing a high yield (74.8 mg mg cat –1 h –1 ) and well-maintained the Faradaic efficiency for over 120 h under ampere-level reduction.
Wen Zhang,Guang-Rui Xu,Tiantian Sun,Jiayi Li,Yu Miao,Zexing Wu,Yang Zhang,Lei Wang
Intermetallic compounds (IMCs) with long-range atomic-scale ordering are an emerging class of efficient and stable electrocatalytic alloy materials. Compared with disordered alloys, IMCs show a better electronic structure and higher mixing enthalpy. Herein, the ordered Ru 4 Fe intermetallic compounds with a diameter of 15 nm on porous carbon (Ru 4 Fe IMCs/C) are synthesized by a sol–gel and annealing steps, the interaction of Ru 4d and Fe 3d orbitals produces an anisotropic electron distribution, which facilitates the adsorption of water molecules and accelerates their dissociation, which exhibit excellent hydrogen evolution at all pH values. At the current density of 10 mA cm −2 , the overpotentials of Ru 4 Fe IMCs/C are 29, 24, and 36 mV in acidic, neutral, and alkaline media for hydrogen evolution reaction (HER), respectively, superior to that of Pt/C catalysts with a mass loading of 20%. Mechanistic studies suggest that the adsorption Gibbs free energy of *H (ΔG *H ) on Ru 4 Fe IMCs/C is closer to 0 eV compared to Ru NPs/C, which facilitates the HER process.
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