Aerobic Conditions Enhance the Photocatalytic Stability of CdS/CdO_x Quantum Dots

Abstract

Photocatalytic H production through water splitting represents an attractive route to generate a renewable fuel. These systems are typically limited to anaerobic conditions due to the inhibiting effects of O . Here, we report that sacrificial H evolution with CdS quantum dots does not necessarily suffer from O inhibition and can even be stabilised under aerobic conditions. The introduction of O prevents a key inactivation pathway of CdS (over-accumulation of metallic Cd and particle agglomeration) and thereby affords particles with higher stability. These findings represent a possibility to exploit the O reduction reaction to inhibit deactivation, rather than catalysis, offering a strategy to stabilise photocatalysts that suffer from similar degradation reactions.

Plastic waste as a feedstock for solar-driven H2 generation

“…S2a) are dispersed in aqueous NaOH, they form a thin Cd oxide/hydroxide shell (CdOx) that prevents photocorrosion. 20,21 Ligand-free QDs were utilised with most substrates as their exposed surfaces tend to correlate with superior catalytic performance (Table S2). 22,23 Oleic acid-capped QDs were used only with PET as they offered slightly higher efficiencies (Table S2), potentially due to a hydrophobic effect favouring substrate-QD interaction.…”

Solvent-controlled O2 diffusion enables air-tolerant solar hydrogen generation

“…The O 2 tolerance induced by DESs compares favourably with examples of O 2 -tolerant H 2 evolution from the literature (TableS5). A range of CdS-based photocatalysts[33][34][35] achieve O 2 tolerances between 40-80%; air can even increase the activity of CdS by suppressing photocorrosion 36. These studies typically operate at high H 2 production rates due to high electron donor concentrations, closed photoreactors and often high light intensities, where O 2 in the solution and the reactor headspace is rapidly depleted by reduction to H 2 O, effectively generating anaerobic conditions in situ; often indicated by an observed lag period before H 2 evolution occurs.…”

ZnSe Nanorods as Visible‐Light Absorbers for Photocatalytic and Photoelectrochemical H2 Evolution in Water

“…[2] Among the most active materials are chalcogenide nanocrystals based on CdS and CdSe. [3] Despite the remarkable activities and stabilities shown by these materials, [4] the toxicity and carcinogenic nature of cadmium represents ac onsiderable obstacle for their wide-spread application. Carbon-based materials,s uch as carbon nitride, [5] carbon dots, [6] and conjugated organic polymers [7] have recently been introduced as environmentally benign alternatives.W hile these materials are inexpensive and usually non-toxic,t heir performances have yet to match those of Cd-based photocatalysts to achieve high quantum yields for aqueous H 2 production without precious and carcinogenic metals.…”