Delaminated CoAl‐Layered Double Hydroxide@TiO₂ Heterojunction Nanocomposites for Photocatalytic Reduction of CO₂

Abstract

Photocatalytic reduction offers an attractive route for CO2 utilization as a chemical feedstock for solar fuels production but remains challenging due to the poor efficiency, instability, and/or toxicity of current catalyst systems. Delaminated CoAl‐layered double hydroxide nanosheets (LDH‐DS) combined with TiO2 nanotubes (NTs) or nanoparticles (NPs) are promising nanocomposite photocatalysts for CO2 reduction. Heterojunction formation between visible light absorbing delaminated CoAl nanosheets and UV light absorbing TiO2 nanotubes greatly enhances interfacial contact between both high aspect ratio components relative to their bulk counterparts. The resulting synergic interaction confers a significant improvement in photoinduced charge carrier separation, and concomitant aqueous phase CO2 photocatalytic reduction, in the absence of a sacrificial hole acceptor. CO productivity for a 3 wt% LDH‐DS@TiO2‐NT nanocomposite of 4.57 µmol gcat‐1 h‐1 exhibits a tenfold and fivefold increase over that obtained for individual TiO2 NT and delaminated CoAl‐LDH components respectively and is double that obtained for 3 wt% bulk‐LDH@TiO2‐NT and 3 wt% LDH‐DS@TiO2‐NP catalysts. Synthesis of delaminated LDH and metal oxide nanocomposites represents a cost‐effective strategy for aqueous phase CO2 reduction.

Heterostructured Catalysts for Electrocatalytic and Photocatalytic Carbon Dioxide Reduction

“…Kumar et al investigated respective contributions of delaminated CoAl‐LDH‐DS thickness (thickness between 2 and 4 nm in contrast to parent CoAl‐LDH, 40 nm) and TiO 2 morphology (nanotubes NTs vs NPs) over synthesized CoAl‐LDH‐DS/TiO 2 heterostructures ( Figure A). [139] . High‐resolution transmission electron microscopy (HRTEM) images (Figure 16B) revealed close contact between CoAl‐LDH‐DS and TiO 2 NT/NPs indicative of abundant heterojunctions while DRUVS plot (Figure 16C) confirmed heterostructure formation as evident from UV absorption across longer wavelengths.…”

Preparation of an In2S3/TiO2 Heterostructure for Enhanced Activity in Carbon Dioxide Photocatalytic Reduction

“…Therefore, the interleaved type II heterojunction can be formed between the two semiconductors. Such energy band arrangement structure is considered to be beneficial to the separation of photogenerated charge carriers, [31] and the suitable band structure of In 2 S 3 /TiO 2 composite can be used for photocatalytic CO 2 reduction reaction.…”

Recent Progress on Nanostructured Layered Double Hydroxides for Visible‐Light‐Induced Photoreduction of CO2

“…Designing a heterojunction structure in photocatalysts is a vital method to enhance the photocatalytic performance by tuning the internal electronic structure. Traditional semiconductor (such as: MoS 2 , [24] Cu 2 O, [25] CeO 2 , [26] TiO 2 , [20f,27] ZnO, [28] and g ‐C 3 N 4 , [29] et al .) were successfully integrated with LDHs and the synergic interaction in heterostructure catalysts performed efficient activity in reducing CO 2 (Table 1).…”