Photoelectrochemical (PEC) water splitting promises a solution to the problem of large-scale solar energy storage. However, its development has been impeded by the poor performance of photoanodes, particularly in their capability for photovoltage generation. Many examples employing photovoltaic modules to correct the deficiency for unassisted solar water splitting have been reported to-date. Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages. We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved. This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.

中文翻译：

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能够通过氧化铁和硅进行无辅助的太阳能水分解。

光电化学（PEC）分解水有望解决大规模太阳能存储的问题。但是，其发展受到光阳极性能差的阻碍，特别是在其产生光电压的能力方面。迄今为止，已经报道了许多采用光伏模块来纠正无辅助太阳能水分解的缺陷的例子。在这里，我们表明，通过使用赤铁矿的原型光阳极材料作为研究工具，表面上或附近的结构紊乱是低光电压的重要原因。我们开发了一种简便的再生长策略来减少表面紊乱，因此可实现0.45 V（相对于可逆氢电极）的开启电压。