Browsing by Author "Yao, Qingxia"
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- Dual-Regulated Ru by Alloying and Metal-Substrate Interaction for Energy-Efficient Hydrazine Oxidation-Paired Hydrogen ProductionPublication . Zhang, Qijing; Wang, Jingshu; Li, Haibo; Zeng, Suyuan; Li, Rui; Yao, Qingxia; Chen, Hongyan; Meng, Lijian; Qu, Konggang; Meng, LijianOverall water splitting (OWS) is the most potential method for large-scale hydrogen production, but the high-potential and sluggish oxygen evolution reaction (OER) greatly impedes its efficacy. Coupling the low-potential hydrazine oxidation reaction (HzOR) with the cathodic hydrogen evolution reaction (HER) has drawn widespread attention with energy-saving advantage and safe products, which necessitates the elaborate design of advanced bifunctional electrocatalysts. Herein, only using two complexes of Ru and Pd with 2,2′-bipyridine, the novel RuPd alloy/N-codoped carbon (RuPd/NC) composite was originally synthesize by direct mixing and pyrolysis, showing superior dual activity for HER and HzOR. Particularly, to deliver the current density of 10 mA cm−2, RuPd/NC merely needs the potentials of −8 and −42 mV for alkaline HER and HzOR, far outperforming Pt/C and being most advanced among the previously studied counterparts. Moreover, the two-electrode overall hydrazine splitting (OHzS) needs ultrasmall voltages of 0.042 and 0.239 V to achieve 10 and 100 mA cm−2, displaying great energy-saving feature. Moreover, the better activity for neutral HER, HzOR and OHzS on RuPd/NC was also found compared with Pt/C. The theoretical simulations uncover the water dissociation at Ru site with the greatly reduced energy barrier followed by the H desorption on the adjacent Pd site for HER, and the optimum activation energy on Ru site for HzOR, crediting to the synergistic regulation of alloying effect and metal-substrate interaction.
- Ir Nanoparticles Synergistically Regulated by B, N Co-Doping in Carbon for pH-Universal Bifunctional Electrocatalysts towards Energy-Efficient Hydrogen ProductionPublication . Huang, Hongli; Meng, Lijian; li, Haibo; Li, Rui; Zeng, Suyuan; Yao, Qingxia; Chen, Hongyan; Qu, Kong-GangThe ultralow-potential hydrazine oxidation reaction (HzOR) can be integrated with hydrogen evolution reaction (HER) to construct the overall hydrazine splitting (OHzS) system, thus realizing energy-saving hydrogen production. Meanwhile, the real electrocatalytic processes normally involve the constantly changed pH and also need to operate under different pH conditions. Therefore, designing advanced pH-universal electrocatalysts with high compatibility for HER and HzOR is of greatly practical significance. Herein, ultrafine Ir nanoparticles embedding in B, N-codoped carbon (Ir/BNC) were facilely synthesized with one Ir-based complex and boric acid by simple mixing and pyrolysis. To reach the current density of 10 mA cm−2, the bifunctional Ir/BNC merely demands the low potentials of −4.8/-6.3/-38.5 mV for HER, 7.5/157.8/330.1 mV for HzOR, and 19/236/358 mV for OHzS in the alkaline, neutral and acidic electrolytes, respectively, all greatly outperforming commercial Pt/C and displaying the huge energy-saving advantage for pH-universal hydrogen generation over the conventional water splitting. Underlyingly, the codoping of abundant B and N heteroatoms with different electronic modulation effects can play synergistical roles to Ir active sites, endowing with the pH-universal multifunctionality as well as the boosted intrinsic unit activity. Additionally, the large surface area, rich pores and highly graphitized carbon also collectively ensure the remarkable apparent performance for bifunctional HER and HzOR. This work supplies a promising strategy for exploiting pH-universal HER and HzOR bifunctional electrocatalysts, greatly potential to the practical energy-efficient hydrogen generation.