This study aims to understand the effects of functional agents such as capping agents, stabilizers, surfactants and additives in shape-controlled synthesis of nanomaterials. The well-defined Pt(100) single crystal sur...This study aims to understand the effects of functional agents such as capping agents, stabilizers, surfactants and additives in shape-controlled synthesis of nanomaterials. The well-defined Pt(100) single crystal surface was used as a model to investigate its interaction with citrate, a capping agent that is often used in shape-controlled synthesis of nanomaterials. It demonstrated that, through a systematic study of electrochemical cyclic voltammetry, the presence of citrate in solution could increase the current peak density of hydrogen adsorption at high potential (j p,L ), while decrease proportionally the current peak density of hydrogen adsorption at low potential (j p,S ). Furthermore, the increase of citrate concentration shifted negatively the peak potentials (E p,L and E p,S ) of both j p,L and j p,S . The results indicated that the interaction of citrate with Pt(100) surface could induce increasing the (100) surface domains of two-dimensional long range order (2D-(100)), and decreasing the (100) surface domains of one-dimensional short range order (1D-(100)). It also revealed that the interaction of citrate with Pt(100) surface could stabilize the 2D-(100) structure. The findings gained in this study implied that the citrate may lead to form stable 2D-(100) domains on Pt nanoparticles upon the shape-controlled synthesis of Pt nanomaterials.展开更多
Fast surface dynamic processes of thiocyanate adsorbed on a nanostructured Pt microelectrode were studied by in situ step-scan time-resolved microscope FTIR spectroscopy(in situ SSTR-MFTIRS) at a time resolution of 10...Fast surface dynamic processes of thiocyanate adsorbed on a nanostructured Pt microelectrode were studied by in situ step-scan time-resolved microscope FTIR spectroscopy(in situ SSTR-MFTIRS) at a time resolution of 100 s.It was found that SCN adsorbs preferentially on Pt surface through N atom at low potential,while through S atom at high potential.The potential-induced orientation conversion between N-and S-bounded forms is very reversible,and occurs only within 2 ms after potential alternation.However,the rate constant(4*103s-1) of conversion from N-to S-bounded adsorption is nearly double to that of the reverse process(2*103s-1).The difference in kinetics of two processes may be explained through the hard-soft acid-base principle.展开更多
In this paper,we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier,via the alcohol reduction and the sulfuric acid treatment.The prepared catalysts were microscopically characterized by X-...In this paper,we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier,via the alcohol reduction and the sulfuric acid treatment.The prepared catalysts were microscopically characterized by X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),electron spectroscopy(EDAX),and transmission electron micros-copy(TEM).We tested the electrochemical performance of the prepared catalysts using an electrochemical workstation and in situ infrared spectroscopy(FTIR).The results showed that the acid-treated AC-PtNi/G catalysts had a more uniform dispersion and with the increased of treatment time,the particle size of the catalyst became smaller.And the electrocatalytic performance of the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h was significantly better than that of the untreated PtNi/G catalyst.Its electrochemically active surface area was 76.63 m^(2)/g,and the peak current density value for catalytic oxidation of ethanol was 1218.83 A/g,which was 10 times that of ordinary commercial Pt/C catalyst.The steady-state current density value of 1100 s was 358.77 A/g,and it has excellent anti-CO toxicity performance.It was determined that a sulfuric acid treatment controlled catalyst particle size and increased the electrocatalytic activity of the catalytic oxidation of ethanol.展开更多
基金financially supported by the National Natural Science Foundation of China (21021002 and 20921120405)
文摘This study aims to understand the effects of functional agents such as capping agents, stabilizers, surfactants and additives in shape-controlled synthesis of nanomaterials. The well-defined Pt(100) single crystal surface was used as a model to investigate its interaction with citrate, a capping agent that is often used in shape-controlled synthesis of nanomaterials. It demonstrated that, through a systematic study of electrochemical cyclic voltammetry, the presence of citrate in solution could increase the current peak density of hydrogen adsorption at high potential (j p,L ), while decrease proportionally the current peak density of hydrogen adsorption at low potential (j p,S ). Furthermore, the increase of citrate concentration shifted negatively the peak potentials (E p,L and E p,S ) of both j p,L and j p,S . The results indicated that the interaction of citrate with Pt(100) surface could induce increasing the (100) surface domains of two-dimensional long range order (2D-(100)), and decreasing the (100) surface domains of one-dimensional short range order (1D-(100)). It also revealed that the interaction of citrate with Pt(100) surface could stabilize the 2D-(100) structure. The findings gained in this study implied that the citrate may lead to form stable 2D-(100) domains on Pt nanoparticles upon the shape-controlled synthesis of Pt nanomaterials.
基金supported by the National Natural Science Foundation of China (21073152,20833005,20933004,and 21021002)the Fundamental Research Funds for the Central Universities (2010121021 and2012121019)+1 种基金Program for New Century Excellent Talents in University(NECT-11-0301)Outstanding Young Scientific Talents Cultivation Plan of Colleges in Fujian Province (JA10003)
文摘Fast surface dynamic processes of thiocyanate adsorbed on a nanostructured Pt microelectrode were studied by in situ step-scan time-resolved microscope FTIR spectroscopy(in situ SSTR-MFTIRS) at a time resolution of 100 s.It was found that SCN adsorbs preferentially on Pt surface through N atom at low potential,while through S atom at high potential.The potential-induced orientation conversion between N-and S-bounded forms is very reversible,and occurs only within 2 ms after potential alternation.However,the rate constant(4*103s-1) of conversion from N-to S-bounded adsorption is nearly double to that of the reverse process(2*103s-1).The difference in kinetics of two processes may be explained through the hard-soft acid-base principle.
基金This work was supported by the National Natural Science Foundation of China(Nos.51864040,51974167)the Natural Science Fund of Inner Mongolia Autonomous Region,China(No.2018LH02006).
文摘In this paper,we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier,via the alcohol reduction and the sulfuric acid treatment.The prepared catalysts were microscopically characterized by X-ray diffractometry(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),electron spectroscopy(EDAX),and transmission electron micros-copy(TEM).We tested the electrochemical performance of the prepared catalysts using an electrochemical workstation and in situ infrared spectroscopy(FTIR).The results showed that the acid-treated AC-PtNi/G catalysts had a more uniform dispersion and with the increased of treatment time,the particle size of the catalyst became smaller.And the electrocatalytic performance of the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h was significantly better than that of the untreated PtNi/G catalyst.Its electrochemically active surface area was 76.63 m^(2)/g,and the peak current density value for catalytic oxidation of ethanol was 1218.83 A/g,which was 10 times that of ordinary commercial Pt/C catalyst.The steady-state current density value of 1100 s was 358.77 A/g,and it has excellent anti-CO toxicity performance.It was determined that a sulfuric acid treatment controlled catalyst particle size and increased the electrocatalytic activity of the catalytic oxidation of ethanol.
