Platinum-based Nanocatalysts For Synergic Catalytic Reforming Of Methanol Into Hydrogen At Low Temperatures

Hydrogen(H2),characterized by environmental benignity and high energy density,has been recognized as one of the most promising replacement energy resources.With the development of hydrogen-based fuel cells,aqueous-phase reforming of methanol(CH3OH)has become a research hotspot for large-scale H2 production,because it is inexpensive and can in situ release the required H2 with a high gravimetric density of 18.8 percent by weight.To date,supported platinum(Pt)catalysts consisting of metallic Pt(Pt0)nanoparticles(NPs)have triggered extraordinary interest for oxidizing CH3OH because of their notable effectiveness at multiple conditions and the facts that they generate environmentally friendly oxidized products.Nevertheless,owing to the high kinetic and thermodynamic stability of CH3OH,its conversion into H2 requires extremely elevated temperatures(200-350?)and high pressures(2.5-5.0 MPa),which is far below the requirements of practical applicationsAmong the solutions proposed to activate such a catalytic process,the efficiency of Pt NPs is often enhanced by the selection of support materials,by increasing its dispersion and/or by adjusting the electronic structures of the active metals.The key role of highly dispersed Pt particles deposited on oxide supports and more generally the specific high activity of metal oxide supports toward CH3OH decomposition compared to pure metals has been demonstrated.The electronic and geometric effects associated with bimetallic NPs have also been reported,whose architectural configuration involves two metals,can be surface engineered to obtain random alloys,segregated or core-shell structures.With this regard,the formation of alloys enables the change in the electronic density of states(ligand effect),and/or decreases the number of multiple-fold adsorption sites by partially blocking the surface(ensemble effect),owing to the unique interactions between neighbouring metals.These changes influence the substrate adsorption properties on the catalyst surface,resulting in unique catalytic activity and selectivity compared with monometallic counterparts.However,although catalytic performance can be modified as a result of alloying,additional elucidation of the catalytically active species during dehydrogenation of CH3OH to H2 is required.The research scheme of this study is as follows:(1)In this paper,PtSn/Al2O3 nanoparticles was synthesized by a simple thermal treatment method.It is observed that Sn is doped into the Pt lattice,and electrons are transferred from Sn to Pt,forming an electron-rich Pt0 and metastable Pt2+species.The electronic rich Pt loaded on the surface of Al2O3 nanoflakes with high specific surface area is the active center of the low-temperature catalytic reforming of methanol to produce hydrogen,which can be the key factor to improve the catalytic performance.(2)The shell controllable Pt@Au/MoS2 catalyst was prepared by the impregnation method.Unique electronic structures of Pt?-and Au+ were formed caused by the electronic interaction among Au,core layer Pt and support MoS2,which leads to the improvement of catalytic performance and reveals the role of the surface interface electronic structure for methanol reforming to produce hydrogen.The MoS2 carrier with a layered structure can also increases the hydrogen generation rate and realizes the reforming of small molecules of Ci biomass derivatives such as methanol,formaldehyde,and formic acid to produce hydrogen at low temperature and normal pressure.In summary,this paper proposes the role of Pt-based catalysts with electron-rich Pt?-species supported on a high specific surface area support in the catalytic reforming of methanol to hydrogen production.The mechanism uncovered here not only pave a new avenue for designing of high active energy catalysts,but also contributes to a deep understanding of hydrogen production reaction from biomass derivatives solution.