A microbial electrolysis cell (MEC) has been regarded as an emerging new technology for the biohydrogen production from various organic substances, even from wastewater. One major problem is, however, that methane dominates produced gases in a long-term operation. Here we report that a photo-assisted MEC (PAMEC) is an efficient way to produce hydrogen with a p-type semiconductor cathode. When Cu₂O coated with MoS₂ as cocatalyst (MoS₂/Cu₂O) is employed, only hydrogen with essentially no methane and carbon dioxide was produced from acetate at −0.8 V bias under visible light illumination at a rate of 2.72 m³H₂ m⁻³d⁻¹. No appreciable performance degradation is observed over 50 days of operation. At lower bias voltage, methane and carbon dioxide begins to be produced. Energy efficiency based on input electricity and hydrogen yield are 225% and 3.4, respectively. This excellent feature of PAMEC is attributed to p-type semiconductor characteristics of Cu₂O and proton reduction activity of MoS₂. Electrons generated from acetate oxidation at the anode are photoexcited to the conduction band at the Cu₂O acquiring enough reduction potential to reduce protons. The concept of PAMEC can be extended to wastewater treatment for the hydrogen production.

微生物电解池（MEC）已被视为一种新兴的新技术，可用于从各种有机物质（甚至是废水）生产生物氢。然而，一个主要问题是，在长期运行中，甲烷在产生的气体中占主导地位。在这里，我们报道光辅助MEC（PAMEC）是一种通过p型半导体阴极生产氢的有效方法。若Cu ₂ ö涂覆的MoS ₂作为助催化剂（MOS ₂ / Cu的₂ O）采用，只能用基本上没有甲烷和二氧化碳的氢从下可见光照明乙酸在-0.8偏压V bias在2.72微米的速率产生³高₂ m ^-3 d ^-1。在运行50天后未观察到明显的性能下降。在较低的偏置电压下，甲烷和二氧化碳开始产生。基于输入电和氢产率的能效分别为225％和3.4。PAMEC的这一优异特性归因于Cu ₂ O的p型半导体特性和MoS _2的质子还原活性。阳极乙酸盐氧化产生的电子在Cu ₂ O处被光激发到导带，从而获得足够的还原电势来还原质子。PAMEC的概念可以扩展到用于制氢的废水处理。