考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催...考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催化剂晶相结构与催化性能的关联。结果表明,Ga_(2)O_(3)的晶相结构与CO_(2)氧化乙苯脱氢性能密切相关,γ-Ga_(2)O_(3)表现出最佳的催化性能,在550℃乙苯转化率达54.7%,苯乙烯选择性为98.6%,循环使用6次后,催化活性仍无明显降低。γ-Ga_(2)O_(3)具有最多的中强酸位、最高的四配位Ga(Ⅳ)百分比和最大的比表面积与孔体积,有利于乙苯的吸附活化、C—H键的解离和催化剂容碳能力的提升,从而使其表现出最佳的催化性能。展开更多
Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unr...Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unresolved.Herein,we report bimetallic PdAu electrocatalysts(PdAu@CC) with low Pd loadings for selective semi-hydrogenation of terminal alkynes through an intermetallic hydrogen spillover pathway.The optimized PdAu@CC catalysts with a Pd molar fraction of 4 % demonstrate exceptional performance in converting acetylene benzene to vinyl benzene,achieving 97.5 % selectivity and 78.2 % Faradaic efficiency at a low potential of -0.17 V vs.RHE,outperforming monometallic Au@CC and Pd@CC.Mechanistic investigations reveal that highly dispersed Pd sites in the Au matrix efficiently dissociate water to generate active H^(*) intermediates.Au sites activate alkynes and promote alkenes desorption,which effectively avoid over-hydrogenation of alkynes.Kinetically favorable Pd-to-Au hydrogen spillover enables selective alkynes-to-alkene hydrogenation,suppressing competitive hydrogen evolution.This work highlights the intermetallic hydrogen spillover as a strategic pathway for designing dual-activesite electrocatalysts with high performance in alkyne semi-hydrogenation.展开更多
文摘考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催化剂晶相结构与催化性能的关联。结果表明,Ga_(2)O_(3)的晶相结构与CO_(2)氧化乙苯脱氢性能密切相关,γ-Ga_(2)O_(3)表现出最佳的催化性能,在550℃乙苯转化率达54.7%,苯乙烯选择性为98.6%,循环使用6次后,催化活性仍无明显降低。γ-Ga_(2)O_(3)具有最多的中强酸位、最高的四配位Ga(Ⅳ)百分比和最大的比表面积与孔体积,有利于乙苯的吸附活化、C—H键的解离和催化剂容碳能力的提升,从而使其表现出最佳的催化性能。
基金the Basic and Applied Basic Research Foundation of Guangdong Province (2023A1515012288)the Fundamental Research Funds for the Central Universities (D5000210829)+1 种基金the Fundamental Research Funds for the Central Universities (D5000210601)the Innovation Foundation for the Doctor Dissertation of Northwestern Polytechnical University (cx2024027)。
文摘Electrocatalytic semi-hydrogenation of alkynes offers a sustainable pathway for synthesizing functionalized olefins,yet challenges in achieving high selectivity and Faradaic efficiency at low overpotentials remain unresolved.Herein,we report bimetallic PdAu electrocatalysts(PdAu@CC) with low Pd loadings for selective semi-hydrogenation of terminal alkynes through an intermetallic hydrogen spillover pathway.The optimized PdAu@CC catalysts with a Pd molar fraction of 4 % demonstrate exceptional performance in converting acetylene benzene to vinyl benzene,achieving 97.5 % selectivity and 78.2 % Faradaic efficiency at a low potential of -0.17 V vs.RHE,outperforming monometallic Au@CC and Pd@CC.Mechanistic investigations reveal that highly dispersed Pd sites in the Au matrix efficiently dissociate water to generate active H^(*) intermediates.Au sites activate alkynes and promote alkenes desorption,which effectively avoid over-hydrogenation of alkynes.Kinetically favorable Pd-to-Au hydrogen spillover enables selective alkynes-to-alkene hydrogenation,suppressing competitive hydrogen evolution.This work highlights the intermetallic hydrogen spillover as a strategic pathway for designing dual-activesite electrocatalysts with high performance in alkyne semi-hydrogenation.
