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

该项目涉及利用清洁、可再生的过程，在太阳直接照射下通过光电化学水分解产生绿色氢。与太阳能发电相比，使用化学键来存储太阳能有望显著降低设备制造成本，以及与能量存储相关的成本。在过去的40年里，研究主要集中在金属氧化物基光催化剂材料上，这些材料只对紫外线（约占太阳光谱的4%）有反应。我们最近首次证明，在蓝光和绿光照射下（高达~ 560nm），金属氮化纳米线上纯水分裂自发产氢，这是迄今为止报道的最长波长。我们进一步发现，目前报道的纳米级光催化剂上太阳能到氢的低转化效率（~1-2%）在很大程度上受到费米水平钉钉和表面能带弯曲的限制。在这个项目中，通过控制镁掺杂剂的掺入来设计金属氮化纳米线的表面电荷特性，我们的目标是将太阳能到氢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，该阵列可以打破太阳能制氢的效率瓶颈。我们的目标是演示一步太阳能制氢，能量转换效率超过15%，与商用太阳能电池的效率相当。该项目还涉及与蒙特利尔IREQ、hydro - quacimbec和CIS科学公司的研究人员密切合作，他们从事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，它将为快速发展的太阳能和氢产业提供范式转变。

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.