Preparation Of Porphyrin-functionalized Biomimetic Membrane And Its Photocatalytic Hydrogen Production Performance

With energy shortages and environmental pollution problems becoming more and more serious,so it is urgent for mankind to explore efficient,environmentally friendly and sustainable energy.Hydrogen energy,as an environment-friendly energy,has attracted great attention.Among many methods of hydrogen production,the photocatalytic water splitting hydrogen production technology has attracted much attention because of its economy and environmental protection.The development of high-efficiency photocatalysts with visible light response is the key to this technology.In this work,Pt⁰@THPP nanocomposites were constructed,and THPP was further chemically grafted onto chloromethyl polysulfone to construct a Pt⁰@THPP-g-PSf photocatalytic functional membrane,which was used for photocatalytic hydrolysis to produce hydrogen.First,Using the prepared meso-tetra(4-hydroxyphenyl)porphyrin(THPP)as the complexing agent,the Pt⁰@THPP nanocomposite was synthesized by the photoreduction method,and characterized by UV-vis,XRD,TEM,electrochemistry,fluorescence and other means.The results show that Pt⁰@THPP has been successfully prepared,and effective electron transfer can occur between excited THPP molecules and Pt nanoparticles,which can inhibit the recombination of electron-hole pairs and improve the efficiency of electron transfer.In addition,the performance of Pt⁰@THPP nanocomposite for photocatalytic decomposition of water to produce hydrogen was studied.Under visible light,Pt⁰@THPP is used as a photosensitizer and catalyst,and AA is used as a sacrificial agent for photocatalytic hydrogen production.The results show that when the p H value is 4 and the AA concentration is 0.2M,it can provide the best photocatalytic efficiency as a sacrificial agent under these conditions and obtain higher hydrogen production,which is 1.0 mmol×g^-1×h^-1.In addition,the reusability of the nanocomposites was studied,and it was found that the nanocomposites exhibited good stability in the photocatalytic process.Further more,The THPP-g-PSf membrane was prepared by surface grafting of THPP onto CMPSf membrane.It was characterized by means of XPS,UV-vis spectrum and IR spectrum,etc.,and it was confirmed that THPP was successfully grafted to the surface of the polysulfone membrane.Furthermore,the THPP-g-PSf membrane is immersed in the H₂PtCl₆ solution,and the Pt⁰@THPP-g-PSf functionalized membrane is obtained after photoreduction treatment..The Pt atom was successfully loaded onto the membrane surface by XPS characterization.Characterization by fluorescence spectroscopy proved that the introduction of Pt can inhibit the recombination of THPP-g-PSf photo-generated electron-hole pairs,thereby facilitating electron/energy transfer and improving photocatalytic activity.In addition,the performance of the Pt⁰@THPP-g-PSf functionalized membrane for photocatalytic water decomposition to produce hydrogen was studied.The prepared THPP-g-PSf membrane and Pt⁰@THPP-g-PSf membrane were used as catalysts for hydrolysis and hydrogen production experiments under visible light.It is found that compared with THPP-g-PSf membrane,Pt⁰@THPP-g-PSf membrane loaded with Pt has higher photocatalytic activity,and its hydrogen production is more than twice that of THPP-g-PSf membrane.The effects of the pH value,sacrificial agent type,sacrificial agent concentration on photocatalytic performance and reusability performance of composite membrane were further investigated.The results showed that when the p H value was 4,sacrificial agent AA and concentration was 0.2M,the catalyst exhibited excellent photocatalytic hydrogen production performance and good stability.