Photoelectrochemical water splitting on metal-nitride nanowire arrays: Breaking the efficiency bottleneck of solar-to-hydrogen conversion

该项目涉及在太阳直接照射下通过光电化学水分解使用清洁、可再生的工艺产生绿色氢。与太阳能发电相比，使用化学键来储存太阳能有望显著降低设备制造成本以及与能量储存相关的成本。在过去的40年里，研究主要集中在基于金属氧化物的光催化剂材料上，这些材料仅对紫外线（UV）光（太阳光谱中约4%）有反应。我们最近首次展示了在蓝光和绿光照射下（最长波长约为560 nm），金属氮化物纳米线上纯水裂解的自发制氢。我们已经进一步确定，目前报道的纳米级光催化剂上的低太阳能-氢转化效率（~1-2%）在很大程度上受到费米能级钉扎和表面能带弯曲的限制。在这个项目中，通过控制Mg掺杂剂的掺入来设计金属氮化物纳米线的表面电荷特性，我们的目标是将太阳能到氢气的转换效率提高一到两个数量级。我们将研究多波段InGaN：Mg纳米线阵列的合成、表征和光催化性能，以突破太阳能转化为氢气的效率瓶颈。我们的目标是展示一步太阳能制氢，其能量转换效率超过15%，与商业太阳能电池的效率相当。该项目还涉及与IREQ，Hydro-Québec和CIS Scientific Inc.的研究人员的密切合作。在蒙特利尔，谁是在开发清洁能源设备和系统的业务。我们坚信，启动这样一个多学科项目迫在眉睫，该项目有望为快速发展的太阳能和氢能行业提供范式转变。

This project is related to the generation of green hydrogen using a clean, renewable process via photoelectrochemical water splitting under direct solar irradiation. Compared to solar electricity, the use of chemical bonds to store solar energy promises significantly reduced device fabrication cost, as well as the cost associated with energy storage. Over the past 40 years, researches have been largely focused upon metal-oxide based photocatalyst materials that are only responsive to ultraviolet (UV) light (~ 4% in solar spectrum). We have recently demonstrated, for the first time, spontaneous hydrogen production from pure water splitting on metal-nitride nanowires under blue and green-lighting irradiation (up to ~ 560 nm), the longest wavelength ever reported. We have further identified that the currently reported low solar-to-hydrogen conversion efficiency (~1-2%) on nanoscale photocatalysts is largely limited by Fermi-level pinning and surface band bending. In this project, by engineering the surface charge properties of metal-nitride nanowires through controlled Mg-dopant incorporation, we aim to enhance the solar-to-hydrogen conversion efficiency by one to two orders of magnitude. We will investigate the synthesis, characterization, and photocatalytic properties of multi-band InGaN:Mg nanowire arrays, that can break the efficiency bottleneck of solar-to-hydrogen conversion. We aim to demonstrate one-step solar-to-hydrogen production with an energy conversion efficiency of more than 15%, which is comparable to the efficiency of commercial solar cells. This project also involves close collaborations with research staff members in IREQ, Hydro-Québec and CIS Scientific Inc. in Montreal, who are in the business of developing clean energy devices and systems. We strongly believe it is of imminent interest to launch such a multidisciplinary project, which is poised to provide a paradigm shift in the rapidly evolving solar energy and hydrogen industries.