Earth-Abundant Transition Metal Catalysts for HX Splitting

地球上储量丰富的用于 HX 裂解的过渡金属催化剂

基本信息

批准号：
8536144
负责人：
David C Powers
金额：
$ 5.22万
依托单位：
HARVARD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-06 至 2014-08-05
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Identification and implementation of clean, sustainable, and affordable energy sources is of paramount importance for both environmental and human health concerns in the future. Sustainable hydrogen-based economies require that hydrogen production from protic media, such as H2O or mineral acids (HX), be coupled to solar power. Closed catalytic cycles for solar-to-hydrogen energy conversion from protic media must meet two technological hurdles: 1) proton reduction to generate dihydrogen, and 2) anion oxidation. A closed cycle for generating H2 from HX requires both proton reduction to form H2 as well as halide oxidation to generate X2. Thus far, molecular catalysts for authentic HX splitting have not been developed. Proof-of-concept systems, which employ chemical traps to promote X2 formation have been developed, however, these systems are not amenable to use in energy storage. This proposal aims to develop inexpensive catalysts based on earth- abundant, first-row transition metals for photochemical HX splitting. If successful, the proposed research would constitute a closed solar-to-hydrogen conversion scheme, in which mineral acids (HX) are converted to H2 and X2 using solar power. The resultant hydrogen could be used as fuel, either by sequestration as a liquid fuel by hydrogenation of small molecule substrates such as CO2 or by being used directly in hydrogen fuel cells. To accomplish the goal of developing a solar-to-hydrogen scheme, low-valent transition metal complexes, capable of proton reduction will first be developed. Simultaneously, investigations of metal dihalide complexes will allow critical requirements for halide oxidation to be defined. To enable the challenging, but necessary, X2 photoelimination, ligands wil be designed to provide access to highly oxidizing excited states. Studies of each of the fundamental steps of HX splitting - proton reduction and halide oxidation - will elucidate fundamental parameters required for each of the constituent half reactions. Informed by the requisite ligand features for each of the fundamental steps of HX splitting, transition metal catalysts will be designed to enable authentic HX splitting photocatalysis to be achieved.

描述（由申请人提供）：确定和使用清洁、可持续且负担得起的能源对于未来的环境和人类健康问题至关重要。可持续的氢经济需要将质子介质（例如 H2O 或无机酸 (HX)）生产的氢与太阳能结合起来。从质子介质将太阳能转化为氢能的闭式催化循环必须满足两个技术障碍：1）质子还原生成氢气，2）阴离子氧化。从 HX 生成 H2 的闭路循环需要质子还原形成 H2 以及卤化物氧化生成 X2。迄今为止，用于真正的 HX 裂解的分子催化剂尚未开发出来。采用化学陷阱促进 X2 形成的概念验证系统已经开发出来，但是这些系统不适合用于能量存储。该提案旨在开发基于地球丰富的第一排过渡金属的廉价催化剂，用于光化学 HX 分裂。如果成功，拟议的研究将构成一个封闭的太阳能到氢气的转化方案，其中利用太阳能将无机酸（HX）转化为H2和X2。所得氢可以用作燃料，可以通过小分子底物（例如二氧化碳）的氢化作为液体燃料封存，也可以直接用于氢燃料电池。为了实现开发太阳能制氢方案的目标，首先将开发能够进行质子还原的低价过渡金属配合物。同时，对金属二卤化物络合物的研究将确定卤化物氧化的关键要求。为了实现具有挑战性但必要的 X2 光消除，配体将被设计为提供高氧化激发态的通道。对 HX 分裂的每个基本步骤（质子还原和卤化物氧化）的研究将阐明每个组成半反应所需的基本参数。根据 HX 分解每个基本步骤所需的配体特征，过渡金属催化剂将被设计为实现真正的 HX 分解才能达到光催化的目的。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Photocrystallographic observation of halide-bridged intermediates in halogen photoeliminations.

DOI：
10.1021/ja508218v
发表时间：
2014-10-29
期刊：
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
影响因子：
15
作者：
Powers, David C.;Anderson, Bryce L.;Hwang, Seung Jun;Powers, Tamara M.;Perez, Lisa M.;Hall, Michael B.;Zheng, Shao-Liang;Chen, Yu-Sheng;Nocera, Daniel G.
通讯作者：
Nocera, Daniel G.

Tandem redox mediator/Ni(ii) trihalide complex photocycle for hydrogen evolution from HCl.