Ultrathin NiAl-Layered Double Hydroxides Grown on 2D Ti₃C₂T_x MXene to Construct Core–Shell Heterostructures for Enhanced Photocatalytic CO₂ Reduction

Abstract

Photocatalytic CO 2 reduction into renewable fuels by sustainable and clean solar energy can be considered as an ideal option to decrease the atmospheric CO 2 level and fulfill the energy requirements. Layered double hydroxides (LDHs) with high surface area, tunable composition as well as exposed active sites have received enormous attention for photocatalytic CO 2 reduction. Herein, a novel NiAl-LDH/Ti 3 C 2 T x nanosheet (NiAl-LDH/TNS) with a core−shell structure was synthesized via an in situ hydrothermal method, and 2D NiAl-LDH coupled with the 2D Ti 3 C 2 T x nanosheet to form a Schottky junction can suppress the back-diffusion of electrons and facilitate the transfer of charge carriers. Benefiting from the feature, the optimized sample with the additive Ti 3 C 2 T x amount of 75 mg (NiAl-LDH/TNS-75) has the photocatalytic CO 2 reduction conversion rate of CO (2128.46 μmol h −1 g −1 ) with the selectivity of CO (90.2%) under visible-light irradiation, which is about 8.6 times higher than that of pristine NiAl-LDH. This work provides a new insight into the construction of novel 2D semiconductor photocatalysts.

Metal-Free Phosphorus-Doped ZnIn2S4 Nanosheets for Enhanced Photocatalytic CO2 Reduction

“…Photocatalytic conversion of CO 2 into renewable fuels and value-added chemicals using sustainable solar energy is a promising technique for resolving the energy and environmental issues simultaneously . A great deal of effort has been devoted to developing high-efficient photocatalysts for CO 2 reduction. − Among the multitudinous types of photocatalytic materials, ZnIn 2 S 4 (ZIS), due to its appropriate band structure, visible-light response, and considerable chemical stability, has exhibited great potential in photocatalytic solar-energy conversion. − Nevertheless, the photocatalytic efficiencies of ZIS are still far from satisfactory due to its poor surface area and severe charge recombination. To improve its photocatalytic performance, some modifications, such as metal ion doping , and coupling with other semiconductor materials, , have been made on ZIS.…”

MXene-Based Photocatalysts and Electrocatalysts for CO2 Conversion to Chemicals

“…Similar to previous cases, although LDH is a typical 2D-layered photocatalyst, it suffers from poor charge mobility, aggregated layers, and rapid charge recombination, leading to low photocatalytic activity [60]. Thus, because of great conductivity and an interfacial Schottky junction, LDH as an n-type semiconductor could be combined with MXenes, leading to enhancement of photocatalyst activity [60].…”

“…Higher electrical conductivity was also found in the low addition of Ti 3 C 2 T x MXene, compared to the addition of other 2D nanomaterials, such as MoS 2 , which contributed to higher catalytic activity [54]. Several reports have also shown the combination of MXenes with other photocatalyst materials, such as g-C 3 N 4 [53], perovskite materials (Cs 3 Bi 2 Br 9 , FAPbBr 3 , CsPbBr 3 , and Cs 2 AgBiBr 6 ) [56][57][58][59], layered double hydroxides (NiAl, Co-Co, and Co 2 Al 0.95 La 0.05 ) [60][61][62], Bi-based photocatalysts (BiOX (X = Cl, Br, I), Bi 2 XO 6 (X = W, Mo), and hybrid Bi 2 O 2 SiO 3 ) [50,63,64], and metal oxides and metal sulfides (TiO 2 , CeO 2 , InVO 4 , CdS, Cd 0.2 Zn 0.8 S, and ZnIn 2 S 4 ) [9,49,53,[65][66][67][68][69].…”

“…Modification of the shape and morphology of MXenes and tandem materials could lead to more efficient photocatalysts by maximizing surface areas as well as the number of adsorption sites [51,71]. MXene-based nanocomposite photocatalysts can be modified into core-shell heterostructures, having an intimate interaction between MXenes and the semiconductor materials [60]. A tandem semiconductor material, such as Co-Co LDH nanosheets, can also be assembled vertically on layered MXenes to accelerate the separation of photogenerated charge carriers [61].…”

SrTiO3@NiFe LDH core–shell composites for photocatalytic CO2 conversion

“…[20][21][22][23][24] The photocatalysis efficiency were roughly compared by CO yield. STONF 2 showed higher photocatalytic performance than reported CoAl LDH, MgAl LDH, ZnCr LDH, NiAl LDH, NiFe LDH, SrTiO 3 based photocatalysts, [25][26][27][28][29][30][31][32][33][34][35][36][37][38] as summarized in Table S1. †…”