Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticl...Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for ORR.The microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.展开更多
为应对当前畜牧业减排形势,促进蛋鸡养殖业健康持续性发展,研究以江苏省中部地区133个蛋鸡养殖场为研究对象,运用生命周期评价法计算蛋鸡养殖全过程碳排放的情况,利用SBM(Slack based measure)模型从经济与环境角度探究蛋鸡养殖的技术...为应对当前畜牧业减排形势,促进蛋鸡养殖业健康持续性发展,研究以江苏省中部地区133个蛋鸡养殖场为研究对象,运用生命周期评价法计算蛋鸡养殖全过程碳排放的情况,利用SBM(Slack based measure)模型从经济与环境角度探究蛋鸡养殖的技术效率。结果显示:该地区只均蛋鸡在整个生命周期中的碳排放为48.55 kg,其中粪便处理是影响碳排放结果的最主要因素,占总排放量的38%。该地区蛋鸡养殖环境效率为0.619 4,低于技术效率(0.667 5),环境效率和技术效率都有较大的提升空间。通过降低投入冗余,只均蛋鸡碳排放量可降低约9.03 kg。蛋鸡养殖具有一定的环境污染性,不同规模之间的蛋鸡养殖效率差异较大,中规模养殖场有明显的环境效率优势。展开更多
基金the support by National Natural Science Foundation of China (52070074, 21806031 and 51578218)Long Jiang Scholars Program (Young Scholar, Q201912)。
文摘Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for ORR.The microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.
