Facile synthesis of hierarchical Cu2O nanocubes as visible light photocatalysts

Santosh Kumar,Christopher M.A Parlett,Mark A Isaacs,Danielle V Jowett,Richard E Douthwaite,Martin C.R Cockett,Adam F Lee

doi:10.1016/j.apcatb.2016.02.038

Abstract

Hierarchically structured Cu2O nanocubes have been synthesized by a facile and cost-effective one-pot, solution phase process. Self-assembly of 5nm Cu2O nanocrystallites induced through reduction by glucose affords a mesoporous 375nm cubic architecture with superior visible light photocatalytic performance in both methylene blue dye degradation and hydrogen production from water than conventional non-porous analogues. Hierarchical nanocubes offer improved accessible surface active sites and optical/electronic properties, which act in concert to confer 200–300% rate-enhancements for the photocatalytic decomposition of organic pollutants and solar fuels.

Highlights

Semiconductor metal oxides have attracted great interest as photocatalytic materials for wide-ranging technological applications including wastewater remediation [1], solar fuels via both H2 production [2] and CO2 reduction [3], and microbial disinfection [4,5,6]
We demonstrate the first facile one-pot and low temperature chemical route to the synthesis of hierarchical 375 nm Cu2O nanocubes comprised of 5 nm sub-units, which exhibit superior visible light photocatalytic performance for methylene blue (MB) decomposition and H2 production from water
The volume-averaged Cu2O crystallite size for the hierarchical nanocubes determined by X-ray diffraction (XRD) of around 20 nm was significantly larger than that derived by transmission electron microscopy (TEM)

Summary

Introduction

Semiconductor metal oxides have attracted great interest as photocatalytic materials for wide-ranging technological applications including wastewater remediation [1], solar fuels via both H2 production [2] and CO2 reduction [3], and microbial disinfection [4,5,6]. The photostability of Cu2O in aqueous media remains a challenge [9] due to its low reduction potential which lies within the band gap This undesirable photocorrosion in water is a strong function of oxide morphology/facet termination [10]. It is of interest to explore whether hierarchical Cu2O nanostructures exhibit enhanced photocatalytic properties; pure hierarchical cuprous oxide [18,23] and nanocomposites thereof with e.g. Cu [24] or ZnO [25], have shown promise in the decomposition of model organic waste water pollutants and in solar fuels production. We demonstrate the first facile one-pot and low temperature chemical route to the synthesis of hierarchical 375 nm Cu2O nanocubes comprised of 5 nm sub-units, which exhibit superior visible light photocatalytic performance for methylene blue (MB) decomposition and H2 production from water.

Nanocube synthesis

Methylene blue photodegradation

Hydrogen evolution

Results and discussion

Conclusions