Kun Xiong

Ni-doped Mo2C nanowires supported on Ni foam as a binder-free electrode for enhancing the hydrogen evolution performance

In this study, an inexpensive electrocatalyst, Ni-doped Mo2C nanowires, were grown directly on Ni foam via a hydrothermal reaction combined with a carburization process. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and linear scanning voltammetry (LSV) were used to scrutinize the catalysts and their electrochemical performance. The results showed that the designed NiMo2C/NF catalyst displays enhanced catalytic activity toward hydrogen production with a low onset overpotential of 21 mV. For driving a cathodic current density of 100 mA cm−2, it only needs an overpotential of 150 mV. Such excellent performance of NiMo2C/NF could be ascribed to the high intrinsic activity from a synergistic function of Ni and Mo2C, as well as to the exposure of more Ni-doped Mo2C sites provided by the high aspect ratio of a one-dimensional (1D) structure and rich surface area.

Pd-induced Pt(IV) reduction to form Pd@Pt/CNT core@shell catalyst for a more complete oxygen reduction†

We describe a facile and controllable process for preparing Pd@Pt/CNT core@shell catalysts for the oxygen reduction reaction (ORR) via Pd-induced Pt(IV) reduction on Pd/CNT. The mass-specific activity for the ORR of the Pd@Pt/CNT catalysts is 7–9 times higher than that of the state-of-the-art Pt/C catalysts, but the yield of H2O2, a harmful species for the stability of catalysts, of the former is only 14.1% of that of the latter. The reason for the enhanced activity and the lower H2O2 yield on the Pd@Pt/CNT catalysts was studied by DFT calculations.

Sn and Sb co-doped RuTi oxides supported on TiO2 nanotubes anode for selectivity toward electrocatalytic chlorine evolution

The (Ru0.3Ti0.34Sn0.3Sb0.06)O2–TiO2 nanotubes (TNTs) anode has been prepared via anodization, deposition, and annealing. X-ray diffraction, field-emission scanning electron microscopy, cyclic voltammetry, and linear scanning voltammetry were used to scrutinize the electrodes and the electrochemical activity. The results indicate that highly ordered TNTs with large specific surface area could be implanted with active metal oxides. The catalyst firmly binds with the TNTs and enhances the electrochemical stability of the electrode. It displays high over-potential for oxygen evolution reaction. Accordingly, the constructed (Ru0.3Ti0.34Sn0.3Sb0.06)O2–TNTs anode exhibits a greater potential difference (ΔE) between the evolutions of oxygen and chlorine than that exhibited by the traditional dimensionally stable anode, which is beneficial for improving the selectivity toward chlorine evolution reaction. This superior performance is explained in terms of the surface properties and geometric structure of coated catalyst, as well as the electrochemical selectivity ascribed by the addition of tin and antimony species.

RuO2 loaded into porous Ni as a synergistic catalyst for hydrogen production

Electrolytic hydrogen by renewable electricity such as solar and wind power is considered as a sustainable energy storage approach. In this work, a porous nano/microarchitectured RuO2/Ni composite catalyst has been elaborately designed via a facile and controllable route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were used to scrutinize the catalysts and the electrochemical performance. The designed RuO2/p-Ni catalyst significantly displays enhanced catalytic activity and long-term durability toward hydrogen production compared with a Pt catalyst. The excellent performance of the composite catalyst could be ascribed to the fact that RuO2 can be well incorporated into the constructed porous Ni network with large specific surface area. The presence of RuO2 and the Ni network in pairs on the surface of the composite catalyst may not only result in a synergistically enhanced catalytic effect between RuO2 and the porous Ni network by hydrogen spillover, but also ensure that RuO2 firmly binds with the porous Ni network, consequently ensuring the long-term durability of the catalyst during the whole reaction.

In situ growth of RuO2–TiO2 catalyst with flower-like morphologies on the Ti substrate as a binder-free integrated anode for chlorine evolution

We report a facile and controllable approach to design anodic catalysts with different surface morphologies. The RuO2–TiO2 anodes are directly grown in situ on the surface of Ti substrate under certain hydrothermal conditions. X-ray diffraction, field-emission scanning electron microscopy, energy dispersive X-ray spectra, cyclic voltammetry, and linear scanning voltammetry (LSV) were used to scrutinize the electrodes and the electrochemical activity. The experimental results indicate that solvothermal crystallization in the presence of hydrochloric acid plays a critical role in regulating the catalyst size and microstructure during the nucleation and growth process of RuO2–TiO2. The designed RuO2–TiO2/Ti anode with a nano-flowerlike structure displays significantly enhanced activity toward anodic chlorine evolution reaction (CER) compared to the other two morphology anodes. Such excellent performance of RuO2–TiO2/Ti is explained in terms of the small charge transfer resistance and the unique surface structure with more active sites to be utilized during CER.Graphical abstract

A DFT study on PtMo resistance to SO2 poisoning

Pt is a catalyst in proton exchange membrane fuel cell (PEMFC), and its activity will be degraded in the air due to the existence of SOx impurities. On strategy is introducing of Mo into the Pt catalyst because it can improve the SOx-tolerance capacity. Based on the aforementioned phenomenon, a density function theory (DFT) study on SOx adsorbed on Pt(111) and PtMo(111) was performed to enhance Pt catalytic activity. The adsorption energy of adsorbed species, the net change, partial density of state (PDOS), and d-band center were calculated and analyzed comparatively. The results show that the presence of Mo-atom weakens the S-Pt bond strength and reduces the adsorption energies for SO2, S and SO3 on PtMo(111). Moreover, the Mo atom weakens the effects of SO2 on the PtMo(111) electronic structure and makes the catalyst maintains its original electronic structure after SO2 adsorption as compared with Pt(111).