Hole extraction by design in photocatalytic architectures interfacing CdSe quantum dots with topochemically-stabilized tin vanadium oxide

DOI: 10.1021/jacs.8b09924

Authors: Justin L. Andrews (Texas A&M University) , Junsang Cho (Texas A&M University) , Linda Wangoh (Binghamton University) , Nuwanthi Suwandaratne (University at Buffalo) , Aaron Sheng (University at Buffalo) , Saurabh Chauhan (University at Buffalo) , Kelly Nieto (Texas A&M University) , Alec Mohr (Texas A&M University) , Karthika J. Kadassery (Texas A&M University) , Melissa R. Popeil (Binghamton University) , Pardeep K. Thakur (Diamond Light Source) , Matthew Sfeir (Brookhaven National Laboratory) , David C. Lacy (University at Buffalo) , Tien-lin Lee (Diamond Light Source) , Peihong Zhang (University at Buffalo) , David F. Watson (University at Buffalo) , Louis F. J. Piper (Binghamton University) , Sarbajit Banerjee (Texas A&M University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: November 2018
Diamond Proposal Number(s): 12764 , 16005

Abstract: Addressing the complex challenge of harvesting solar energy to generate energy-dense fuels such as hydrogen requires the design of photocatalytic nanoarchitectures interfacing components that synergistically mediate a closely interlinked sequence of light-harvesting, charge separation, charge/mass transport, and catalytic processes. The design of such architectures requires careful consideration of both thermodynamic offsets and interfacial charge-transfer kinetics to ensure long-lived charge carriers that can be delivered at low overpotentials to the appropriate catalytic sites while mitigating parasitic reactions such as photocorrosion. Here we detail the theory-guided design and synthesis of nanowire/quantum dot hetero-structures with interfacial electronic structure specifically tailored to promote light-induced charge separation and photo-catalytic proton reduction. Topochemical synthesis yields a metastable β-Sn0.23V2O5 compound exhibiting Sn 5s-derived midgap states ideally positioned to extract photogenerated holes from interfaced CdSe quantum dots. The existence of these midgap states near the upper edge of the valence band (VB) has been confirmed and β-Sn0.23V2O5/CdSe heterostruc-tures have been shown to exhibit a 0 eV midgap state-VB offset, which underpins ultrafast sub-picosecond hole transfer. The β-Sn0.23V2O5/CdSe heterostructures are further shown to be viable photocatalytic architectures capable of efficacious hydrogen evolution. The results of this study underscore the criticality of precisely tailoring the electronic structure of semi-conductor components through the design and synthesis of novel compounds and demonstrates the remarkable utility of p-block lone-pair states to effect rapid charge separation necessary for photocatalysis.

Subject Areas: Chemistry, Materials, Energy


Instruments: I09-Surface and Interface Structural Analysis