Directed Assembly of Nanoparticle Catalysts on Nanowire Photoelectrodes for Photoelectrochemical CO₂ Reduction

Abstract

Reducing carbon dioxide with a multicomponent artificial photosynthetic system, closely mimicking nature, represents a promising approach for energy storage. Previous works have focused on exploiting light-harvesting semiconductor nanowires (NW) for photoelectrochemical water splitting. With the newly developed CO2 reduction nanoparticle (NP) catalysts, direct interfacing of these nanocatalysts with NW light absorbers for photoelectrochemical reduction of CO2 becomes feasible. Here, we demonstrate a directed assembly of NP catalysts on vertical NW substrates for CO2-to-CO conversion under illumination. Guided by the one-dimensional geometry, well-dispersed assembly of Au3Cu NPs on the surface of Si NW arrays was achieved with facile coverage tunability. Such Au3Cu NP decorated Si NW arrays can readily serve as effective CO2 reduction photoelectrodes, exhibiting high CO2-to-CO selectivity close to 80% at -0.20 V vs RHE with suppressed hydrogen evolution. A reduction of 120 mV overpotential compared to the planar (PL) counterpart was observed resulting from the optimized spatial arrangement of NP catalysts on the high surface area NW arrays. In addition, this system showed consistent photoelectrochemical CO2 reduction capability up to 18 h. This simple photoelectrode assembly process will lead to further progress in artificial photosynthesis, by allowing the combination of developments in each subfield to create an efficient light-driven system generating carbon-based fuels.

Semiconductor‐Based Photoelectrochemical Conversion of Carbon Dioxide: Stepping Towards Artificial Photosynthesis

“…Recently, Yang et al. demonstrated a direct and facile way to assemble well‐dispersed bimetallic Au 3 Cu nanoparticles on the Si NW surface, which served as a highly efficient photoelectrode for the conversion of CO 2 into CO, with FE=80 % at −0.2 V versus RHE and a large decrease of overpotential (up to 120 mV) compared with that of the same catalyst coupled to a planar silicon photoelectrode . In the presence of Si NWs as photosensitizers to harvest light and transfer electrons to [Co(tpa)Cl]Cl (TPA=tris(2‐pyridylmethyl)amine), the PEC CO 2 reduction to CO was conducted at much less negative potentials than that on the Au/Si electrode.…”

Photoelectroreduction of Building‐Block Chemicals

“…Moreover, the enlarged surface area of NW arrays dilutes the distribution of photogenerated electron/hole flux over their entire surfaces, and therefore relaxes the electrocatalytic turnover requirement of the electrode and lowers the reaction overpotential . This becomes particularly important if photogenerated electrons or holes are used to drive kinetically sluggish reactions . We envisaged that a process similar to PEC water splitting took place on the Si NW photocathode (Figure a).…”

Structure Design and Composition Engineering of Carbon‐Based Nanomaterials for Lithium Energy Storage

“…Moreover, the performance of an electrode material not only depends on the building units but also largely on how they are assembled . As a result, the integration of electrode materials with one, two, and three dimensionalities have become a research hotspot for a long time . These desired structures show great potential to overcome the shortcomings under various conditions, offering an intelligent way to expand the boundaries of LBs.…”