Direct Z-Scheme 0D/2D Heterojunction of CsPbBr₃ Quantum Dots/Bi₂WO₆ Nanosheets for Efficient Photocatalytic CO₂ Reduction

Abstract

Photocatalytic CO2 reduction is an appealing approach to convert solar energy into high value-added chemicals. All-inorganic CsPbBr3 quantum dots (QDs) have emerged as a promising photocatalyst for reducing CO2. However, pristine CsPbBr3 has a low catalytic performance, mainly due to severe charge recombination. Herein, a 0D/2D heterojunction of CsPbBr3 QDs/Bi2WO6 nanosheet (CPB/BWO) photocatalysts is fabricated for photocatalytic CO2 reduction. The CPB/BWO photocatalyst achieves excellent photocatalytic performance: the total yield of CH4/CO is 503 μmol g–1, nearly 9.5 times higher than the pristine CsPbBr3. The CPB/BWO heterojunction also exhibits much-improved stability during photocatalytic reactions. On the basis of various characterization techniques, our investigations verified a direct Z-scheme charge migration mechanism between CsPbBr3 QDs and Bi2WO6 nanosheets. The improved photocatalytic performance is originated from the high spatial separation of photoexcited charge carriers in CPB/BWO, which can also preserve strong individual redox abilities of two components. This work reports an efficient direct Z-scheme heterojunction photocatalytic system based on metal halide perovskites. The novel strategy we proposed may bring up new opportunities for the development of metal halide perovskite photocatalysts with greatly enhanced activities.

Glycine‐Functionalized CsPbBr3 Nanocrystals for Efficient Visible‐Light Photocatalysis of CO2 Reduction

“…In the field of the photocatalysis of CO 2 conversion with MHP NCs‐based photocatalysts, continuous efforts have focused on surface/interface modification [16, 18–24] and heterojunction engineering [25–32] to increase the active sites and improve the separation efficiency of photogenerated carriers, achieving a great improvement in photocatalytic performance over the past few years. However, the long alkyl‐chain capping ligands in conventional MHP NCs will be unfavorable for the CO 2 adsorption and hinder the efficient carrier transport in MHP NCs‐based heterojunctions, [26, 27] which has not yet been recognized extensively.…”

“…[9] TheseM HP NCs have attracted ever-increasing attention recently in the photocatalytic field, [10][11][12][13] for applications such as photocatalysis of H 2 evolution, [14] photodegradation of organic pollutants, [15] photocatalysis of CO 2 reduction, [16] and photocatalytic organic synthesis. [17] In the field of the photocatalysiso fC O 2 conversion with MHP NCs-based photocatalysts, continuouse ffortsh ave focused on surface/interface modification [16,[18][19][20][21][22][23][24] and heterojunction engineering [25][26][27][28][29][30][31][32] to increase the active sites and improve the separatione fficiencyo fp hotogenerated carriers,a chieving ag reat improvementi np hotocatalytic performanceo ver the past few years. However,t he long alkyl-chain capping ligands in conventional MHP NCs will be unfavorable for the CO 2 adsorptiona nd hinder the efficient carriert ransport in MHP NCsbasedh eterojunctions, [26,27] which has not yet been recognized extensively.C onsidering that capping ligandsa re indispensable for the preparation of MHP NCs with good stabilitya nd low surface defect density, the employment of small functional organic molecules as capping ligandsc ould be an ideal solution to maintain colloidals tability andi mprove the photocatalytic CO 2 activity of MHP NCs-based photocatalysts.…”

Perovskite Nanocrystals‐Based Heterostructures: Synthesis Strategies, Interfacial Effects, and Photocatalytic Applications

“…Also, PNCs‐based Z‐scheme heterostructure was reported. Such as, α‐Fe 2 O 3 /Amine‐RGO/CsPbBr 3 , [ 98 ] CsPbBr 3 /Bi 2 WO 6 nanosheets, [ 99 ] and CsPbBr 3 /Ultrathin and Small‐Size Graphene Oxide (USGC)/α‐Fe 2 O 3 . [ 100 ] As shown in Figure 7e, apart from the intrinsic radiative channel, the establishment of Z‐scheme heterostructure in α‐Fe 2 O 3 /Amine‐RGO/CsPbBr 3 provided an additional energy‐transfer pathway for excited‐state electron transfer, which leads to a lower PL intensity level in this Z‐scheme heterostructure than that of the pristine CsPbBr 3 NCs or α‐Fe 2 O 3 /Amine‐RGO.…”

Recent progress in Bi2WO6‐Based photocatalysts for clean energy and environmental remediation: Competitiveness, challenges, and future perspectives

“…The photocatalytic reduction of CO 2 can be enhanced through the morphological control of Bi 2 WO 6 . [ 242 ] As mentioned above, Jiang's group fabricated three‐dimensional Bi 2 WO 6 quantum dots with hollow structures, and exhibited excellent photocatalytic reduction of CO 2 to methanol. [ 79 ] The specific surface area and pore size reached 90.7 m 2 g –1 and 4.7 nm, and its VBM position and CBM position were determined to be 1.95 and ‐1.15 eV, respectively.…”