Kinetic model of hypophosphite oxidation on a nickel electrode was studied in D2O solution in order to reach a better understanding of the oxidation mechanism. In the model;he electrooxidation of hypophosphite undergo...Kinetic model of hypophosphite oxidation on a nickel electrode was studied in D2O solution in order to reach a better understanding of the oxidation mechanism. In the model;he electrooxidation of hypophosphite undergo a H abstraction of hypophosphite from the P-H bond to form the phosphorus-centered radical (PWO2-)-P-., which subsequently is electrochemically reacted with water to form the final product, phosphite. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The process of hypophosphite electrooxidation could be well simulated by this model.展开更多
In this study,we developed a tandem photo-assisted electrochemical(PA-EC)chemical strategy for both energy-saving ammonia/fertilizer synthesis and comprehensive nitrogen-and phosphorus-rich wastewater treatment,in whi...In this study,we developed a tandem photo-assisted electrochemical(PA-EC)chemical strategy for both energy-saving ammonia/fertilizer synthesis and comprehensive nitrogen-and phosphorus-rich wastewater treatment,in which synchronous hypophosphite ion(H_(2)PO_(2)^(-))oxidation to phosphate ion(PO_(4)^(3–))(POR)and nitrate reduction(NO_(3)RR)to ammonia(NH_(3))occur,followed by cascade chemical precipitation to generate struvite.Herein,a bifunctional Cu_(2)O@NiFe_(2)O_(4)Z-scheme heterojunction with a yolk/shell structure and oxygen vacancies(OVs)was designed and developed to optimize the NO_(3)RR/POR.Serving as a key component,the established PA-EC system consisted of a Janus Cu_(2)O@NiFe_(2)O_(4)/NF self-supporting integrated photocathode and a Cu_(2)O@NiFe_(2)O_(4)/NF photocathode with efficient struvite PA-EC synthesis performance under a low cell voltage of 1.6 V vs NHE.Specifically,Janus Cu_(2)O@NiFe_(2)O_(4)/NF photocathode exhibits superior performance with a high NH3 yield of 38.06 mmol L^(-1)and a faradaic efficiency(FE)of 92.31%at 1.6 V vs.NHE and enables ammonia FE over 60%in a broad NO_(3)–concentration window of 0.005–0.5 mol L^(-1).The photoassisted electrochemical catalytic mechanism and reaction pathway for struvite synthesis on Cu_(2)O@NiFe_(2)O_(4)were investigated through a series of experiments and theoretical calculations.The results demonstrated the critical roles of the interfacial electric field,void confinement,and oxygen vacancies in promoting the overall catalytic efficiency.These encouraging results warrant further studies on combined P and N recovery for efficient production of valuable fertilizers.展开更多
基金The work was supported by the Natural Science Foundation of the Education Commission of Hunan Province(No.99C57)
文摘Kinetic model of hypophosphite oxidation on a nickel electrode was studied in D2O solution in order to reach a better understanding of the oxidation mechanism. In the model;he electrooxidation of hypophosphite undergo a H abstraction of hypophosphite from the P-H bond to form the phosphorus-centered radical (PWO2-)-P-., which subsequently is electrochemically reacted with water to form the final product, phosphite. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The process of hypophosphite electrooxidation could be well simulated by this model.
文摘In this study,we developed a tandem photo-assisted electrochemical(PA-EC)chemical strategy for both energy-saving ammonia/fertilizer synthesis and comprehensive nitrogen-and phosphorus-rich wastewater treatment,in which synchronous hypophosphite ion(H_(2)PO_(2)^(-))oxidation to phosphate ion(PO_(4)^(3–))(POR)and nitrate reduction(NO_(3)RR)to ammonia(NH_(3))occur,followed by cascade chemical precipitation to generate struvite.Herein,a bifunctional Cu_(2)O@NiFe_(2)O_(4)Z-scheme heterojunction with a yolk/shell structure and oxygen vacancies(OVs)was designed and developed to optimize the NO_(3)RR/POR.Serving as a key component,the established PA-EC system consisted of a Janus Cu_(2)O@NiFe_(2)O_(4)/NF self-supporting integrated photocathode and a Cu_(2)O@NiFe_(2)O_(4)/NF photocathode with efficient struvite PA-EC synthesis performance under a low cell voltage of 1.6 V vs NHE.Specifically,Janus Cu_(2)O@NiFe_(2)O_(4)/NF photocathode exhibits superior performance with a high NH3 yield of 38.06 mmol L^(-1)and a faradaic efficiency(FE)of 92.31%at 1.6 V vs.NHE and enables ammonia FE over 60%in a broad NO_(3)–concentration window of 0.005–0.5 mol L^(-1).The photoassisted electrochemical catalytic mechanism and reaction pathway for struvite synthesis on Cu_(2)O@NiFe_(2)O_(4)were investigated through a series of experiments and theoretical calculations.The results demonstrated the critical roles of the interfacial electric field,void confinement,and oxygen vacancies in promoting the overall catalytic efficiency.These encouraging results warrant further studies on combined P and N recovery for efficient production of valuable fertilizers.
