Simultaneous Formation of CO and H2O2 from CO2 and H2O with a Ag-MnOx/CaTiO3 Photocatalyst
Simultaneous Formation of CO and H2O2 from CO2 and H2O with a Ag-MnOx/CaTiO3 Photocatalyst
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DOI：
10.1021/acsaem.1c00510
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发表时间：
2021-07-13
影响因子：
6.4
通讯作者：
Yoshida, Hisao
中科院分区：
文献类型：
--
作者：
Soltani, Tayyebeh;Yamamoto, Akira;Yoshida, Hisao
一氧化碳（CO）是化学工业的重要原料，过氧化氢（H2 O2）也是一种具有广泛应用的重要化学品。在这里，发现了一种光催化系统，用于从CO2和H2O同时生产CO和H2 O2，具有高的活性和选择性，而没有任何外部施加的电压和任何消耗的化合物，这是促进通过使用改性的钛酸钙（CaTiO 3）光催化剂与银锰氧化物（Ag-MnOx）双助催化剂。虽然报道了Ag/CaTiO 3（CTO）光催化剂用水还原CO2以形成CO和O-2，但是MnOx物种与银纳米颗粒（NP）的共存不仅将CO形成速率提高了2倍以上，选择性为76%，而且还改变了氧化反应的选择性，并且以99%的高选择性形成H2 O2而不是O-2。Ag纳米颗粒通过光激发电子促进CO2还原成CO，而沉积在CaTiO 3表面的Mn（III）氧化物物种通过空穴促进水氧化成H2 O2，HCO 3-作为反应介质。生成的CO容易从水溶液分离到气相，H2 O2稳定地储存在HCO 3水溶液中。这种光催化系统可以利用稳定和普遍存在的分子（CO2和H2O）同时产生反应性和有用的分子（CO和H2 O2），这意味着它可以将光能转化为可储存的化学能，以提高可持续性。
Carbon monoxide (CO) is an important feedstock for the chemical industry, and hydrogen peroxide (H2O2) is also an important chemical with versatile applications. Here, a photocatalytic system was discovered for the simultaneous production of CO and H2O2 from CO2 and H2O with both high activity and selectivity without any externally applied voltage and any consumption of chemical compounds, which was promoted by using a calcium titanate (CaTiO3) photocatalyst modified with a silver-manganese oxide (Ag-MnOx) dual cocatalyst. Although a Ag/CaTiO3(CTO) photocatalyst was reported to reduce CO2 with water to form CO and O-2, the coexistence of MnOx species with silver nanoparticles (NPs) not only improved the CO formation rate more than 2 times with a selectivity of 76% but also changed the selectivity of the oxidative reaction and forms H2O2 instead of O-2 with a high selectivity of 99%. The Ag NPs promoted the CO2 reduction to CO by the photoexcited electrons, and the Mn(III) oxide species deposited on the CaTiO3 surface contributed to the water oxidation to H2O2 by the positive holes in the aid of HCO3- as a reaction mediator. The produced CO is easily separated from the aqueous solution to the gas phase, and the H2O2 is stably stored in the aqueous HCO3- solution. This photocatalytic system can utilize the stable and ubiquitous molecules (CO2 and H2O) to produce reactive and useful molecules (CO and H2O2), concurrently, meaning that it can convert photoenergy to storable chemical energy to increase sustainability.