Oxygen vacancy enhancing mechanism of nitrogen reduction reaction property in Ru/TiO2

To search the new effective nitrogen reduction reaction(NRR)electrocatalyst is very important for the ammonia-based industry.Herein,we reported the design of a novel NRR electrocatalyst with Ru NPs loaded on oxygen-vacancy TiO2(Ru/TiO2-Vo).Structural characterizations revealed that oxygen vacancy was loaded in the matrix of Ru/TiO2-Vo.Electrocatalytic results indicated that Ru/TiO2-Vo showed good NRR performance(2.11μg h^-1 cm^-2).Contrast tests showed that NRR property of Ru/TiO2-Vo was much better than those of Ru/TiO-12(B)(0.53μg hcm^-2)and Ru/P25(0.42μg h^-1 cm^-2).Furthermore,density functional theory calculation results indicated catalytic mechanism of NRR and rate-determining step(*N2+1/2 H2→*N+*NH)was the potential-determining step with the overpotential requirement of 0.21 V.A combination of electronic structure analysis and catalytic measurement shed light on the synergistic effect of Ru and oxygen vacancy on the NRR performance.

Defect CTF derived Ru-based catalysts for high performance overall water splitting reaction

Research on water-splitting electrocatalysts is crucial to establishing a solution to the energy crisis.Herein,we report a facile bottom-up strategy for the preparation of high performance supported electrocatalysts for overall water-splitting reaction via a rationally designed defect covalent triazine frameworks(CTFs)support.Specifically,defect CTFs are obtained via binary-precursor polymerization,followed by loading Ru nanoparticles(Ru/D-CTFs-900)with high HER performance at a current density of 10 mA cm-2.The overpotential is only 17 mV.Calcination of the resultant Ru–RuO2/D-CTFs-300 in air,produces excellent OER performance with 190 mV overpotential(at 10 mA cm-2).Furthermore,overall water splitting measurements reveal the potential of 1.47 V,which is better than the majority of the reported Ru-based catalysts.Moreover,density functional theory calculation results show that excellent electrocatalytic properties are attributed to the synergistic effect of Ru nanoparticles and carbon support.

Directly imaging the in-situ chemical transformation of nickel cubane nanoclusters for promoting electrocatalytic urea-oxidation reaction

We report the stepwise in-situ manipulation of a nickel cubane nanocluster capped with a specially designed multidentate ligand [Ni^(Ⅱ)_(4)(HL)_(3)(CH_(3)O)(CH_(3)OH)_(3)](CH_(3)COO)(Ni_(4),H_(3)L=(E)-3-((2-hydroxy-3-mehoxybenzylidene)amino)propane-1,2-diol) to firstly [Ni^(Ⅱ)_(4)(HL)_(3)(CH_(3)O)(CH_(3)OH)_(2)(H_(2)O)](CH_(3)COO)(Ni4-1min) and finally to [Ni^(Ⅱ)_(4)(HL)_(3)(CH_(3)O)(H_(2)O)_(3)](CH_(3)COO)Ni4-20h)during the urea electrolysis.A combination of mass spectrometry,single crystallography and pair distribution function were employed to analyze the structural correlations of this catalyst in crystal/solution/gas phases for confirming the dynamic ligand replacement while preserving the cubic Ni4 core during catalysis.The key feature of their structures is that:(i)three ligands wrap the Ni_(4)O_(4)cubane center on one side forming the rounded outside of a calix;(ii)the opposite flat side containing labile methanol as the active site.This structure facilitates the binding of the substrate to the active central nickel atoms during catalysis.Furthermore,due to the different modes of packing,the structure of Ni4-20 h sustains two-dimensional(2D)net of open space while the structures of Ni4 and Ni4-1 min have only closed void inaccessible to solvent molecules or ions.Interestingly,the overpotential initially decreased(up to 45 min)until it is stabilized.The result showed a low potential of 1.32 V(urea oxidation reaction(UOR))at 10 mA·cm^(-2)as reflected in the Gibbs free energy decrease of~0.4 eV from Ni4 to Ni4-20 h.This work demonstrates a convincing approach for elucidating the exact nature of the active clusters in electrocatalytic process,and confirms that in-situ modification of electrode materials might alter the direct electronic interaction between substrate and active sites in improving the catalytic performance.