Solar driven efficient direct conversion of methane to multicarbon oxygenates

Abstract

SUtilizing sunlight to produce valuable chemicals from methane serves as a promising green strategy, exploiting the hydroxyl radicals generated by water photooxidation to accomplish methane C–H activation. However, the selective...

Ultrahigh efficiency CH4 photocatalytic conversion to C1 liquid products over cheap and vacancy-rich CeO2 at 30 °C

“…With illumination time of 2 h, a high yield rate of C1 liquid product of 3.88 mmol (g cat h) −1 was reached, equivalent to a space time yield of 928 g (kg cat h) −1 (an important industrial production index). This is 1–3 orders of magnitude larger than previous reports 18,19,21,22,34,41–43 (see Fig. 3f and Table S1 in the ESI†), which is accompanied by a high C1 selectivity of 97.73% (HCHO and HCOOH selectivity of 76.33%).…”

Nitrogen-Doped Titanium Dioxide for Selective Photocatalytic Oxidation of Methane to Oxygenates

“…Combined with the analysis results, N-doped contents and sites are the main reason for the improvement of carrier separation efficiency. 30 The photocatalytic CH 4 oxidation performance was evaluated in a quartz reactor at 60 °C using only water as the oxidant, 31 and the reaction illustration is displayed in Scheme S1. Figure 4a and Table S3 show that CO, methanol, aldehyde, propanal, and acetone were detected in the gas phase over A-N-TiO 2 under irradiation with a total product yield of 252.39 μmol•g −1 •h −1 , 5.97 times (42.26 μmol•g −1 •h −1 ) over N-TiO 2 -500, 9.13 times (27.64 μmol•g −1 •h −1 ) over A/R-N-TiO 2 , and 88.25 times (2.86 μmol•g −1 •h −1 ) over R-N-TiO 2 .…”

Photocatalytic Conversion of Methane: Current State of the Art, Challenges, and Future Perspectives

“…For liquid–solid reactions, the • CH 3 radical tends to react with • OOH (O 2 + e – + H + → • OOH) to form CH 3 OOH in the presence of O 2 , which can be reduced to CH 3 OH and then oxidized to HCHO/CO 2 . Besides, the • CH 3 radical can also react with • OH or H 2 O to generate CH 3 OH. ,, The selectivity of liquid products is related to their ability to desorb on the catalyst surface. In addition, syngas (CO and H 2 ) can be obtained through methane reforming with H 2 O (gas) or CO 2 , which are known as steam reforming of methane (CH 4 + H 2 O → 3H 2 + CO, Δ G 0 298 K = 142 kJ mol –1 ) and dry reforming of methane (CH 4 + CO 2 → 2H 2 + 2CO, Δ G 0 298 K = 171 kJ mol –1 ), respectively. − In general, the conversion processes are thermodynamically unfavorable without the participation of oxygen, such as nonoxidative coupling of methane, steam reforming of methane, and dry reforming of methane.…”

“…42 As for the indirect route, the C−H bond cleavage can be switched on by the generated oxygen radicals, such as • OH. 43 The highly oxidative 31,44,45 The selectivity of liquid products is related to their ability to desorb on the catalyst surface. In addition, syngas (CO and H 2 ) can be obtained through methane reforming with H 2 O (gas) or CO 2 , which are known as steam reforming of methane (CH 4 + H 2 O → 3H 2 + CO, ΔG 0 298 K = 142 kJ mol −1 ) and dry reforming of methane (CH 4 + CO 2 → 2H 2 + 2CO, ΔG 0 298 K = 171 kJ mol −1 ), respectively.…”