Boundary Growth Of Tungsten Carbide (Mo) On Carbon Carrier And Its Electrocatalytic Application

In recent years, the electrocatalysis have provided the chance to solve the environmental and energy problems. The catalyst is the key in the electrocatalytic reaction. Compared with the Pt-based catalyst, the transition metal nitrides are cheaper and has higher corrosion resistance, thus received intensive attentions in the electrocatalytic fields. The small size of the nitrides is beneficial to the exposure of the active site and the improvement of catalytic performance. Therefore, the design and synthesis of transition metal nitrides with small size and high dispersion is of great significance. Based on the above analysis, our study are concentrated in three aspects as follows:(1) A effective “1-methylimidazole(1-MD)-fixation” strategy was developed to anchor the phosphotungstic acid with small molecules(PW12, tungsten source) on CNTs carrier. After sintering and nitridation, the effective combination of WN particles and CNTs were successfully achieved. Meanwhile, the particle sizes of WN could be tuned as 2 nm, 3 nm and 4 nm. This effective complex was derived from the strong interaction between1-MD and POMs(or CNTs). WN/CNTs has a good HER catalytic activity and could enhance the performance of Pt for MOR as co-catalysts. In addition, this method could also is used to prepare the WN/rGO complex with small sized WN particles.(2) The “1-methylimidazole(1-MD)-fixation” strategy is simple to operate and could be further extended. We have carried out a systematic study for this method to realize the effective combination of a variety of small-sized and high-dispersed transition metal nitride particles(WN/Mo2N) with various carbon carriers(carbon nanotubes/carbon black). The prepared binary and ternary catalysts were be applied to HER. Among them, the ternary catalysts showed excellent HER catalytic activity and stability, which should be attributed to the synergistic effect of the two transition metal compounds.(3) Tungsten nitride/graphitized carbon(WN/GC) composite have been synthesized by electrostatic attraction method. In the synthesis, the dicyandiamide were used as carbon source. The close contact between the small-sized WN particles and the thin carbon layer was realized. The close contact caused by the electrostatic interaction between dicyandiamide and PW12 promote conductivity of WN/GC,which is conducive to the improvement of co-catalytic activity in MOR. Experimental results showed that the Pt-WN/GC-3 catalyst had an outstanding performance of methanol oxidation(928 mA mg-1Pt) and the ability to resist CO poisoning.