Rational design of phosphorus-doped cobalt sulfides electrocatalysts for hydrogen evolution

Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction(HER)since it can adjust the electronic structure,activesite,and phase.The reported studies mainly focus on designing P doped C0S2,while otherphases of cobalt sulfide,such as Co1-xS and Co9S8 doped with P are rarely investigated for HER electrocatalysts.Herein,various cobalt sulfides(including CoSg/Co1-xS,Co1-xS,and Co9S8)doped with P are anchored on carbon cloth through a facile hydrothermal method.Among tested electrocatalysts,P doped Co1-xS exhibits excellent electrocatalytic performance with an overpotential of 110 and 165 mV(vs.RHE)for currentdensities of 10 and 100 mA·cm^-2,respectively.Density functional theory calculations reveal that P doped Co1-xS possesses a smaller bandgapand more optimal hydrogen adsorption sites than pristine Co1-xS.This work initially investigates various cobalt sulfides doped with P and furthergets in sight into the activity improvement mechanism of P dopi ng,which could guide the desig n of earth-abunda nt HER electrocatalysts for the"hydrogen economy".

Embedding wasted hairs in Ti/PbO_(2) anode for efficient and sustainable electrochemical oxidation of organic wastewater

Despite of the hazardous risk of Pb^(2+) leakage, lead dioxide has been attributed as a quasi-ideal anode material with high oxygen evolution potential, excellent conductivity, good stability and low cost in electrochemical oxidation wastewater treatment technique. In this study, a novel Ti/PbO_(2) anode was fabricated by embedding raw materials that are readily and cheaply available, i.e., hairs. The structure-activity relationship of the new electrode was firstly revealed by material and electrochemical characterizations. Then different levels of pollutants (azo dye, phenol and maleic acid) were used to investigate the electrochemical oxidation performance of the new electrode. Finally, the accelerated electrode lifetime and Pb^(2+) leakage tests were carried out. Results showed that the embedded hairs changed the preferential crystallographic orientation of PbO_(2) and decreased the grain size. Hairs introduced additional roughness and active sites, and decreased the electrode impedance, especially under 5 mg/cm^(2) of embedding amount. The removal efficiencies of different target pollutants were enhanced more or less by embedding appropriate amount of hairs, depending on the current density, but loading excessive hairs had a negative effect. The accumulation of intermediate products during phenol degradation was also changed by the hairs. The new electrode could undergo ~550 h of harsh electrolysis. It is also relieved that the Pb^(2+) leakage was found to be suppressed during this long-term electrolysis process.