陆地热泉自然硫日光催化无机碳有机转化的作用机制研究

This project will utilize interdisciplinary research methods of mineralogy, semiconducting photoelectric chemistry and environmental geochemistry, with the aim to identify the fine mineralogical characteristics and semiconducting physicochemical properties of natural sulfur collected from terrestrial hot springs. We will specially address the key scientific problem of “the semiconducting mineralogical characteristics of natural sulfur allotropes and the electron transfer and CO2 activation mechanisms involved in the process of photoreductive conversion of CO2 into small molecule organics”. To achieve this goal, we will study the detailed process of CO2 photoreduction by natural sulfur in simulated environmental conditions of early Earth, identify the defect sites, active sites and radical-like intermediates on the surface of natural sulfur, calculate the conversion efficiency of photon-photoelectron-electron as well as CO2 to organics, study the possible activation and reduction pathway of CO2, and interpret the dynamic mechanism of electron/photoelectron transfer and transformation on the interface of reductive substances/natural sulfur/CO2. Dedicating to the new forming mechanism and theoretical model to comprehend the abiotic pathway of life origination involved by natural sulfur photocatalysis, this project is of great scientific value and can provide new evidences of substance transformation and energy resource to support the terrestrial chemical origin of life on early Earth.

本项目拟采用矿物学、半导体光电化学与环境地球化学交叉学科研究手段，在查明现代陆地热泉中自然硫精细矿物学与半导体物理化学特性的基础上，围绕“地表热泉自然硫同素异形体半导体矿物学特性及其光催化还原CO2为小分子有机质的电子转移与活化机制”这一关键科学问题，模拟开展早期地表自然硫光催化还原CO2的精细过程研究，鉴定自然硫表面缺陷位、CO2活性反应位与自由基类中间产物，计算光子—光电子—电子与碳转化效率，探讨CO2被活化并被还原转化的可能途径，阐明光电子/电子在还原态物质/自然硫/CO2界面转移与转化的动力学机制。提出自然硫光催化作用诱导非生物途径生命起源物质形成的机制与理论模型，为地球生命陆地化学起源学说提供能量来源与物质转化科学证据。

太阳光能是地表最重要的自然能量形式之一，驱动着无机矿物与有机生物共同参与下的多种自然作用。自然硫矿物是早期地球陆地热泉中丰度最高的非金属单质矿物，发挥着关键但未被充分查明的日光能量吸收和物质转化作用。本项目重点围绕自然硫晶体化学调控光催化活性和驱动能量与物质转化的界面电子转移机制这一关键科学问题，对自然硫矿物的半导体性质、光电化学活性、界面电子传递微观机制和地球早期非生物合成有机物的模型进行深入研究。研究发现自然硫光电子能量是目前所发现的地表日光激发下矿物可产生的最高光电子能量，阐明自然硫在光子—光电子—价电子转化过程的热、动力学机制，揭示自然硫分子构型调控光电子能量与界面硫原子活性微观机制，提出自然硫光化学作用诱导非生物途径生命起源物质形成的机制与模型，获得分子晶体矿物促进能量转化和物质循环的规律性认识。共发表学术论文13篇，其中SCI论文8篇。