Do Sacrificial Donors Donate H₂ in Photocatalysis?

Rational Design of Metal Halide Perovskite Nanocrystals for Photocatalytic CO2 Reduction: Recent Advances, Challenges, and Prospects

“…The DFT calculations revealed that the reaction activity follows the order (112) > ( 102) > (002) > (110). 34 Accordingly, the polyhedron-shaped CsPbBr 3 with (112) facets would be more efficient photocatalysts than hexapods and cube-shaped CsPbBr 3 toward CO 2 reduction. Besides, when discussing facet effects, it is better to estimate the surface areas of different NCs.…”

“…From the solar-to-fuel conversion point of view, controlling the oxidative half-reaction is as important as the CO 2 reduction counter-reaction. − In most reported MHP photocatalytic systems, sacrificial donors such as methanol, isopropanol, and benzyl alcohol are often employed to promote the CO 2 reduction on MHP NCs. ,, It is important to evaluate the oxidative half-reaction since the degradation of sacrificial donors may lead to the overestimation of reduction products.…”

Current dilemma in photocatalytic CO2 reduction: real solar fuel production or false positive outcomings?

“…Various chemical additives, including acetonitrile (CH 3 CN) [60,61], bicarbonate (HCO 3 − ) [62], and NaOH [63], thus are adopted to improve the solubility of CO 2 in H 2 O, ensuring a sufficient supply of CO 2 molecules to the reactive sites. However, despite the effectiveness of these sacrificial reagents and/or chemical additives in improving the reaction efficiency, little attention has been paid to the possible influence of these chemical reagents on the quantification of CO 2 reduction products (Scheme 1b) [50,51].…”

“…2c that H 2 and CO are produced in the reaction system with the incidence of UV-C light, the evolution rates of which are comparable or even larger than many reported values attributed to the photoreduction of CO 2 when they were divided by the regular amounts of photocatalysts employed in literature (several tens to one hundred of milligram), regardless of the presence of water, CO 2 and NaHCO 3 additive or not. Here we consider the generation of H 2 and CO under the irradiation of UV enhanced Xe lamp reasonable, since the molecular bonds of the organic contaminants on the inner wall of photoreactors and/or in the reaction solvents could be broken by UV disinfection effects, which is similar to the light induced decomposition and/or oxidation of hole scavengers during the photocatalysis process, resulting in the release of small molecules [49,51]. While in contrast, gas products can hardly be found when the reaction is carried out under the irradiation of traditional Xe lamp (Fig.…”

“…) pose a huge challenge in the identification and quantification of the real reduction products [42,43]. Particularly, it has been reported that both the organic substances involved in the preparation of photocatalysts [44][45][46][47][48] and the decomposition products of sacrificial reagents and/or reaction additives [49][50][51] may decompose to small molecules, such as hydrogen (H 2 ), CO, and methane (CH 4 ), causing the overestimation of catalytic activities or even false positive results. In this regard, isotopic 13 CO 2 labelling experiments are suggested to verify whether the carbon-containing products are derived from CO 2 or carbonaceous impurities [10,36,40,52].…”