Core@Shell CsPbBr₃@Zeolitic Imidazolate Framework Nanocomposite for Efficient Photocatalytic CO₂ Reduction

Abstract

The proper energy band structure and excellent visible-light responses enable halide perovskites as potential photocatalysts for CO 2 reduction, but the conversion efficiency is still low due to the serious radiative recombination, low CO 2 capturing ability, and poor stability. Here we illustrate the design and synthesis of a halide perovskite@metal−organic framework (MOF) composite photocatalyst with enhanced CO 2 reduction activity. A facile in situ synthetic procedure is employed to directly grow a zinc/cobalt-based zeolitic imidazolate framework (ZIF) coating on the surface of CsPbBr 3 quantum dots. The CsPbBr 3 @ZIF composite shows largely improved moisture stability, CO 2 capturing ability, and charge separation efficiency. Moreover, the catalytic active Co centers in ZIF-67 can further accelerate the charge separation process and activate the adsorbed CO 2 molecules, which leads to enhanced catalytic activity for gaseous CO 2 reduction. This work would provide new insight for designing excellent perovskite/MOF-based catalysts.

Encapsulating Perovskite Quantum Dots in Iron‐Based Metal–Organic Frameworks (MOFs) for Efficient Photocatalytic CO2 Reduction

“…While the composite photocatalysts containing both MAPbI 3 QDs and Fe exhibit significant improvement of photocatalytic activity for CO 2 reduction, generating remarkably enhanced yields for both CO and CH 4 , suggesting Fe is the vital catalytic site for photocatalytic CO 2 reduction. Particularly,MAPbI 3 @PCN-221(Fe 0.2 )exhibits the highest photocatalytic activity,a chieving 104 mmol g À1 of CO and 325 mmol g À1 of CH 4 .T he calculated value for electron consumption rate (R electron = (2Yield CO + 8Yield CH 4 )/25 h) is 112 mmol g À1 h À1 ,w hich is about 31 and 8t imes larger than those of corresponding pristine PCN-221(Fe 0.2 )a nd PCN-221(Fe) counterparts,r espectively.T he values of R electron for MAPbI 3 @PCN-221(Fe x )( 78-112 mmol g À1 h À1 )a re also much larger than those of composite photocatalysts of LHP QDs with MOFs coating (15-30 mmol g À1 h À1 ), [25] which can be ascribed to the close contact between MAPbI 3 QDs and Fe catalytic sites.Asshown in Figure 2a,the values of R electron and the selectivity of CH 4 generation gradually decrease along with the increase of Fe content in MAPbI 3 @PCN-221(Fe x ), which may be ascribed to the competitive light absorption between MAPbI 3 QDs and PCN-221(Fe x ), resulting in reduced number of transferred electrons from MAPbI 3 QDs to Fe catalytic sites along with the increase of Fe content in PCN-221(Fe x ).…”

“…Moreover,i ti se xcited to note that the MAPbI 3 @PCN-221(Fe x )c omposite photocatalysts display an obvious improvement of stability compared with relatively stable PCN-221(Fe x ), in which MAPbI 3 @PCN-221(Fe x )p hotocatalysts display linear productions of CO and CH 4 with at ime over 80 h, as observed in Figures S5a and S5b,w hile PCN-221(Fe x )p hotocatalysts can only be stable within 30 h ( Figures S5c and S5d), after that time they decompose and lose the catalytic activity.Meanwhile,the stability of MAPbI 3 QDs in MAPbI 3 @PCN-221(Fe x )i sa lso much more stable than those of reported LHP QDs based photocatalysts for CO 2 reduction. [24][25][26][27] Thus MAPbI 3 @PCN-221(Fe x )composite photocatalysts display significantly enhanced yields for CO 2 reduction, 25-38 times higher than those of corresponding PCN-221(Fe x )inthe absence of perovskite QDs (Figure 2b), in which MAPbI 3 @PCN-221(Fe 0.2 )gets arecord-high yield of 1559 mmol g À1 for photocatalytic CO 2 reduction to CO (34 %) and CH 4 (66 %), 38 times higher than that of pristine PCN-221(Fe 0.2 )(41 mmol g À1 ). To our knowledge,this is the highest value among diverse perovskite QDs based catalysts for photocatalytic CO 2 reduction up to now.T he results of XRD measurements of MAPbI 3 @PCN-221(Fe 0.2 )a nd PCN-221-(Fe 0.2 )a fter photocatalytic reaction show that the pattern of MAPbI 3 @PCN-221(Fe 0.2 )a grees well with that of simulated PCN-221 ( Figure S7), indicating the crystal structure of MAPbI 3 @PCN-221(Fe 0.2 )c an retain its integrity after the photocatalytic reaction.…”

“…[17][18][19][20] In this regard, lead halide perovskite (LHP) NCs are ordinarily endowed with high defect tolerance and long photogenerated carrier lifetime,t riggering their widespread applications in photovoltaic and optoelectronic devices. [24][25][26][27][28][29][30][31][32][33] In photocatalytic CO 2 reduction, LHP QDs have been demonstrated to be capable of converting CO 2 into CO and CH 4 . [24][25][26][27][28][29][30][31][32][33] In photocatalytic CO 2 reduction, LHP QDs have been demonstrated to be capable of converting CO 2 into CO and CH 4 .…”

“…[21][22][23] Most recently,L HP quantum dots (QDs) have also been actively pursued as catalysts in photocatalytic fields. [24][25][26][27][28][29][30][31][32][33] In photocatalytic CO 2 reduction, LHP QDs have been demonstrated to be capable of converting CO 2 into CO and CH 4 . [27] Loading LHP QDs on graphene oxide [26] or g-C 3 N 4 [24] can facilitate the charge separation, bringing forth improved catalytic performance for CO 2 reduction.…”

Recent Progress and Development in Inorganic Halide Perovskite Quantum Dots for Photoelectrochemical Applications

“…Consequently, the CsPbBr 3 /a‐TiO 2 composite exhibited a marvelous 6.5‐fold improvement on the photocatalytic CO 2 reduction performance in comparison with the individual CsPbBr 3 . In another case, zeolitic imidazolate framework (ZIF) was reported to encapsulate the CsPbBr 3 for enhancing the stability and photocatalytic CO 2 reduction activity . The mechanism for the enhanced stability and photocatalytic activities of the CsPbBr 3 @ZIF nanocomposite was similar to that of the TiO 2 encapsulation mentioned above.…”