The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are m...The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.展开更多
氮化硅是一种良好的载体,具有较高的水热稳定性和机械稳定性,其表面的氨基基团能够较好地锚定金属,显著提高金属分散度。但是,商品氮化硅比表面积较低,对金属分散作用仍然有限。因此,以自制的高比表面积氮化硅(Si_(3)N_(4))为载体,通过...氮化硅是一种良好的载体,具有较高的水热稳定性和机械稳定性,其表面的氨基基团能够较好地锚定金属,显著提高金属分散度。但是,商品氮化硅比表面积较低,对金属分散作用仍然有限。因此,以自制的高比表面积氮化硅(Si_(3)N_(4))为载体,通过浸渍法制备了不同Ru负载量(质量分数分别为0.5%、1.0%和2.0%)的催化剂(分别为0.5%Ru/Si_(3)N_(4)、1.0%Ru/Si_(3)N_(4)和2.0%Ru/Si_(3)N_(4)),并以商品氮化硅(Si_(3)N_(4)-C)为载体制备了2.0%Ru/Si_(3)N_(4)-C催化剂作为对照组。表征了催化剂的理化性质,测试了其在300℃、0.1 MPa下的CO_(2)加氢反应活性。结果显示,与Si_(3)N_(4)-C相比,Si_(3)N_(4)的比表面积较高(502 m^(2)/g),Si_(3)N_(4)作为载体显著提高了金属分散度,降低了金属粒径,催化剂暴露出更多的活性位点。0.5%Ru/Si_(3)N_(4)的金属粒径较小,展现出强的H_(2)吸附能力,H难以解吸,抑制了中间物种CO加氢生成CH_(4)。随着Ru负载量增加,金属粒径增大,催化剂的CH_(4)选择性更好。Ru/Si_(3)N_(4)系列催化剂中,2.0%Ru/Si_(3)N_(4)的CH_(4)选择性较高(98.8%)。空速为10000 m L/(g·h)时,0.5%Ru/Si_(3)N_(4)的CO选择性为88.2%。与2.0%Ru/Si_(3)N_(4)相比,2.0%Ru/Si_(3)N_(4)-C的金属粒径更大,活性位点较少,活性更低。2.0%Ru/Si_(3)N_(4)和2.0%Ru/Si_(3)N_(4)-C的CO_(2)转化率分别为53.1%和9.2%。Si_(3)N_(4)有效提高了金属分散度,提高了催化剂的CO_(2)加氢反应活性;通过调控Ru负载量控制催化剂金属粒径,可实现对产物CO或CH_(4)选择性的调控。展开更多
通过深过冷凝固实验对Co-Ru包晶合金中不同相的析出及演化行为进行了研究。采用熔融玻璃净化与循环过热相结合的方法对该合金的深过冷实验获得了217 K(0.12 T L)的最大过冷度。结合经典形核理论的计算结果,在全过冷度范围内ξ相始终作...通过深过冷凝固实验对Co-Ru包晶合金中不同相的析出及演化行为进行了研究。采用熔融玻璃净化与循环过热相结合的方法对该合金的深过冷实验获得了217 K(0.12 T L)的最大过冷度。结合经典形核理论的计算结果,在全过冷度范围内ξ相始终作为先析相优先从熔体中析出。当过冷度(ΔT)小于临界过冷度(ΔT*≈180 K)时,合金凝固组织表现为典型的包晶组织,此时包晶相的析出依赖于ξ相的形态改变;当ΔT>ΔT*时,虽然ξ相仍为先析相,但是包晶相α的析出不再依赖于ξ相,而是直接从过冷熔体中析出并与ξ相竞争长大。随着过冷度的增大,包晶相的相对含量先增加后减少最后再次增加。展开更多
A supported amorphous Ru-Co/ZrO 2 catalyst was prepared by using formaldehyde as reduetant. The amorphous character of the catalyst was estimated by XRD, TG-DTA and SEM. The amorphous Ru-Co/ZrO 2 catalyst has higher s...A supported amorphous Ru-Co/ZrO 2 catalyst was prepared by using formaldehyde as reduetant. The amorphous character of the catalyst was estimated by XRD, TG-DTA and SEM. The amorphous Ru-Co/ZrO 2 catalyst has higher selectivity than Ru/ZrO 2 in the selective hydrogenation of benzene to cyclohexene when the experiments were run in simulated production conditions. Presence of Co in the catalyst favored the selectivity of Ru-Co/ZrO 2 but decreased its activity.展开更多
The RuCoB/ZrO2 catalyst was prepared by chemical reduction method,in which Ru was an active component,Co was a promoter and ZrO2 was a dispersant.The influences of the different contents of Co and ZrO2 and t...The RuCoB/ZrO2 catalyst was prepared by chemical reduction method,in which Ru was an active component,Co was a promoter and ZrO2 was a dispersant.The influences of the different contents of Co and ZrO2 and the different reducing agents on the catalytic characteristics were studied.The results indicated that the characteristics of the catalysts reduced by KBH4 were better than that by formaldehyde.When Co/Ru ratio was 2% and Ru/ZrO2 ratio was 13%,the snythetically catalytic characteristics of RuCoB/ZrO2 was the best, and γ40 and S40 reached 14239h-1 and 758%, respectively.展开更多
基金the National Natural Science Foundation of China(No.22271203)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(No.KF2021005)the Collaborative Innovation Center of Suzhou Nano Science and Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905).
文摘The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.
文摘氮化硅是一种良好的载体,具有较高的水热稳定性和机械稳定性,其表面的氨基基团能够较好地锚定金属,显著提高金属分散度。但是,商品氮化硅比表面积较低,对金属分散作用仍然有限。因此,以自制的高比表面积氮化硅(Si_(3)N_(4))为载体,通过浸渍法制备了不同Ru负载量(质量分数分别为0.5%、1.0%和2.0%)的催化剂(分别为0.5%Ru/Si_(3)N_(4)、1.0%Ru/Si_(3)N_(4)和2.0%Ru/Si_(3)N_(4)),并以商品氮化硅(Si_(3)N_(4)-C)为载体制备了2.0%Ru/Si_(3)N_(4)-C催化剂作为对照组。表征了催化剂的理化性质,测试了其在300℃、0.1 MPa下的CO_(2)加氢反应活性。结果显示,与Si_(3)N_(4)-C相比,Si_(3)N_(4)的比表面积较高(502 m^(2)/g),Si_(3)N_(4)作为载体显著提高了金属分散度,降低了金属粒径,催化剂暴露出更多的活性位点。0.5%Ru/Si_(3)N_(4)的金属粒径较小,展现出强的H_(2)吸附能力,H难以解吸,抑制了中间物种CO加氢生成CH_(4)。随着Ru负载量增加,金属粒径增大,催化剂的CH_(4)选择性更好。Ru/Si_(3)N_(4)系列催化剂中,2.0%Ru/Si_(3)N_(4)的CH_(4)选择性较高(98.8%)。空速为10000 m L/(g·h)时,0.5%Ru/Si_(3)N_(4)的CO选择性为88.2%。与2.0%Ru/Si_(3)N_(4)相比,2.0%Ru/Si_(3)N_(4)-C的金属粒径更大,活性位点较少,活性更低。2.0%Ru/Si_(3)N_(4)和2.0%Ru/Si_(3)N_(4)-C的CO_(2)转化率分别为53.1%和9.2%。Si_(3)N_(4)有效提高了金属分散度,提高了催化剂的CO_(2)加氢反应活性;通过调控Ru负载量控制催化剂金属粒径,可实现对产物CO或CH_(4)选择性的调控。
基金National Basic Research Program of China(2011CB610404)
文摘通过深过冷凝固实验对Co-Ru包晶合金中不同相的析出及演化行为进行了研究。采用熔融玻璃净化与循环过热相结合的方法对该合金的深过冷实验获得了217 K(0.12 T L)的最大过冷度。结合经典形核理论的计算结果,在全过冷度范围内ξ相始终作为先析相优先从熔体中析出。当过冷度(ΔT)小于临界过冷度(ΔT*≈180 K)时,合金凝固组织表现为典型的包晶组织,此时包晶相的析出依赖于ξ相的形态改变;当ΔT>ΔT*时,虽然ξ相仍为先析相,但是包晶相α的析出不再依赖于ξ相,而是直接从过冷熔体中析出并与ξ相竞争长大。随着过冷度的增大,包晶相的相对含量先增加后减少最后再次增加。
文摘A supported amorphous Ru-Co/ZrO 2 catalyst was prepared by using formaldehyde as reduetant. The amorphous character of the catalyst was estimated by XRD, TG-DTA and SEM. The amorphous Ru-Co/ZrO 2 catalyst has higher selectivity than Ru/ZrO 2 in the selective hydrogenation of benzene to cyclohexene when the experiments were run in simulated production conditions. Presence of Co in the catalyst favored the selectivity of Ru-Co/ZrO 2 but decreased its activity.
文摘The RuCoB/ZrO2 catalyst was prepared by chemical reduction method,in which Ru was an active component,Co was a promoter and ZrO2 was a dispersant.The influences of the different contents of Co and ZrO2 and the different reducing agents on the catalytic characteristics were studied.The results indicated that the characteristics of the catalysts reduced by KBH4 were better than that by formaldehyde.When Co/Ru ratio was 2% and Ru/ZrO2 ratio was 13%,the snythetically catalytic characteristics of RuCoB/ZrO2 was the best, and γ40 and S40 reached 14239h-1 and 758%, respectively.
