Direct propylene epoxidation with oxygen using a photo-electro-heterogeneous catalytic system

Abstract

Propylene oxide (PO) is a crucial feedstock in the plastic industry. The direct epoxidation of propylene using O 2 is considered to be the most promising means of producing PO, but it remains challenging. Here, we report on an integrated photo-electro-heterogeneous catalytic system for propylene epoxidation with O 2 . Bismuth vanadate (or TiO 2 ) photocatalyst and Co-based electrocatalyst produce H 2 O 2 and titanium silicalite-1 heterogeneous catalyst epoxidises propylene to PO with the in situ generated H 2 O 2 . This system enables PO production with O 2 as the sole oxidising agent under light irradiation without using H 2 , a sacri cial agent, or external bias. It stably produces PO for 24 h with high selectivity (≥ 98%) under ambient conditions. These results demonstrate the potential of this new catalytic system to produce chemical compounds in an environmentally benign manner.

Steering Catalytic Selectivity with Atomically Dispersed Metal Electrocatalysts for Renewable Energy Conversion and Commodity Chemical Production

“…Although the two catalysts showed similar H 2 O 2 selectivities of ∼60%, the high-temperature-pyrolyzed Co–N/CNT showed substantially higher ORR activity than CoTMPP/CNT, as evidenced by its 400 mV higher onset potential (Figure a,b). Notably, Co–N/CNT showed pH-independent electrochemical H 2 O 2 production performance (Figure c,d), which is distinct from carbon-based catalysts exhibiting high H 2 O 2 production performance only under alkaline conditions. ,,− The pH-universal nature of Co–N/CNT for H 2 O 2 production enabled its use in unprecedented tandem catalytic systems. , By combining a Co–N/CNT electrocatalyst with a photocatalyst and a heterogeneous catalyst, propylene oxide (PO), an industrially important feedstock for plastic production, can be produced in an otherwise-impossible environmentally benign manner in near-neutral media (Figure e) . In this integrated system, a bismuth vanadate visible-light photocatalyst produces electrons that are used to transform O 2 to H 2 O 2 on the Co–N/CNT electrocatalyst.…”

“…CC BY 4.0. (c–e) Reproduced with permission from ref . Copyright 2021 the authors of ref , under exclusive license to Springer Nature.…”

“…10,14,46−48 The pH-universal nature of Co− N/CNT for H 2 O 2 production enabled its use in unprecedented tandem catalytic systems. 32,33 By combining a Co−N/CNT electrocatalyst with a photocatalyst and a heterogeneous catalyst, propylene oxide (PO), an industrially important feedstock for plastic production, can be produced in an otherwise-impossible environmentally benign manner in nearneutral media (Figure 5e). 33 In this integrated system, a bismuth vanadate visible-light photocatalyst produces electrons that are used to transform O 2 to H 2 O 2 on the Co−N/CNT electro- atomically dispersed precious-metal catalysts for the ORR compared to that of conventional NP-based catalysts.…”

“…In this Account, we illustrate our recent efforts to establish preparation methods for atomically dispersed metal catalysts to develop selective and active electrocatalysts for renewable energy conversion and commodity chemical production. This Account provides a discussion of (i) the preparation methods for atomically dispersed metal catalysts − and (ii) their electrocatalytic applications for selective 4e – /2e – ORR, − ,− CO 2 RR competing with HER, , and CER competing with OER. , The key concepts and detailed synthetic chemistry to develop generalized approaches are presented. Next, our findings regarding catalytic trends with respect to the structure of atomically dispersed active sites and insights into selective electrocatalysis are discussed.…”

Review on BiVO4-Based Photoanodes for Photoelectrochemical Water Oxidation: The Main Influencing Factors

“…Bismuth vanadate (BiVO 4 ), as the most promising PEC water oxidation photoanode material, has been attracting researchers’ attention in recent years. − It possesses a narrow band gap that allows it to absorb more visible light. In addition, the valence band position and the conduction band position of BiVO 4 photoanode are, respectively, close to 2.5 and 0 V versus reversible hydrogen electrode (RHE) due to the empty Bi 6p track that overlaps the back-key V 3d-O 2p track, which has strong catalytic capacity of oxygen production (Figure a) .…”