Photoelectrochemical Water-splitting Performance Research Articles

CoNiFe-LDHs decorated Ta3N5 nanotube array photoanode for remarkably enhanced photoelectrochemical glycerol conversion coupled with hydrogen generation

Solar-driven photoelectrochemical (PEC) technology has been widely recognized as a green and sustainable approach to produce fossil-fuel-alternative energy sources, whereas currently its feasibility is still a great challenge due to the lack of high-performance photoanodes. Herein, two-dimensional trimetallic CoNiFe-layered double hydroxides (CoNiFe-LDHs) nanosheets were uniformly anchored on one-dimensional Ta 3 N 5 nanotube arrays used as a novel integrated photoanode. Serving as a hole collector, CoNiFe-LDHs can accelerate hole extraction from photo-excited Ta 3 N 5 towards surface water oxidation reaction (WOR), thus promoting the separation of electron-hole pairs and ultimately markedly improving PEC water-splitting performance. Moreover, the trimetallic CoNiFe-LDHs were more effective in boosting the PEC performance than the three sets of bimetallic LDHs. By further replacing WOR with glycerol oxidation reaction (GOR), the composite photoanode achieved a ten-fold enhancement of solar energy conversion efficiency reaching 0.56% with nearly 100% Faradaic efficiency for concurrent generation of formate and hydrogen. Importantly, the stability of Ta 3 N 5 was dramatically enhanced due to the synergy of CoNiFe-LDHs loading and anodic GOR. The significantly enhanced PEC properties can be mainly attributed to the increased surface active sites, promoted hole extraction and utilization, and particularly the improved charge separation efficiency. This work provides a reference for the fabrication of high-performance Ta 3 N 5 -based photoanodes towards efficient and stable PEC hydrogen generation and the green conversion of biomass derivatives into valuable chemicals. • 2D CoNiFe-LDHs NSs were uniformly anchored on 1D Ta 3 N 5 NAs as an integrated photoanode. • CoNiFe-LDHs loading remarkably enhanced the solar-driven PEC water-splitting performance of Ta 3 N 5 . • Highly efficient and stable PEC H 2 production was achieved due to surface modification and anodic glycerol oxidation. • The enhanced PEC properties originate from increased active sites, promoted hole extraction, faster charge separation.

Effect of Ti foil size on the micro sizes of anodic TiO2 nanotube array and photoelectrochemical water splitting performance

Anodic TiO2 nanotube (NT) array is promising for the flexible and efficient photoanode in photoelectrochemical water splitting (PECWS) cell. However, the photocurrent response of pristine anodic TiO2 NT photoanode in literature has a ca 50 times difference, viz. from 0.05 to 1 mA/cm2. Improvement of the pristine TiO2 NT is the base for achieving a high efficient anode. Here, we examine the size effect in different scale on the PECWS performance with manipulating the macro size of the Ti foil. With decrease of the Ti foil size from 6 to 1 cm2, corresponding to the anodic TiO2 NT growth active area of 3.45 to 0.65 cm2, the photocurrent response increased by 50.6%, achieving 1.13 mA/cm2 at 1.23 VRHE (V versus reversible hydrogen electrode). The Ti foil size also significantly influences the micro sizes of the nanotubes including crystallite size, double wall thickness, inner diameter and tube length, which have profound effects on WS efficiency. The relationships between involved length scales, a span of six orders of magnitude from ten nanometers (10−8 m) to centimeter (10−2 m), and the PECWS efficiency is analyzed and discussed. Transient i-t curves are used to represent the chemical kinetics during the growth of anodic TiO2 NT array. Finally, photon capture scheme is proposed to explain the physics behind the multi length scale effect of the TiO2 NT photoanode. The need of quantitative models during the scale-up of the PECWS process is stressed.

The co-decorated TiO2 nanorod array photoanodes by CdS/CdSe to promote photoelectrochemical water splitting

A cascade structure of TiO2/CdS/CdSe semiconductor heterojunction is synthesized using a three-step technique of facile hydrothermal growth for the enhancement of the photoelectrochemical performances. The optical and photoelectrochemical properties controlled by the deposition processing parameters have been investigated. It is shown that the patterns of semiconductor heterojunction enlarge the absorption range of solar spectra, and improve the properties of the photogenerated charge carriers describing separation and transportation, and reduce the interface resistance between the photoelectrode and electrolyte comparing with the pure TiO2 and CdS-decorated TiO2 nanorod array photoanodes. The higher photocurrent density and photoconversion efficiency are up to 4.23 mA cm−2 and 4.2%, which are the 4.1 and 25.3 times superior than that of the pure TiO2 photoanode. The hydrothermal growth time increment of CdSe yields greater photoelectrochemical water splitting performances. The underlying physics mechanisms have been discussed based on forming a type-Ⅱ energy band alignment structure.

Facile construction TiO2/ZnIn2S4/Zn0.4Ca0.6In2S4 ternary hetero-structure photo-anode with enhanced photo-electrochemical water-splitting performance

Constructing hetero-junction on TiO2 is an effective way to overcome the fast charge recombination and slow charge transfer kinetics, but how to design the junction is still a significant challenge in photo-electrochemical (PEC) water splitting. In this study, a considerable improvement in PEC performance for TiO2 nanotubes was achieved following the introduction of a ternary hetero-junction through depositing ZnIn2S4 (ZIS) and Zn0.6Ca0.4In2S4 (ZCIS) in sequence via a facile hydrothermal method (TiO2/ZIS/ZCIS). The optimized photo-anode exhibited a photocurrent density of 1.07 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE), to be 3.96 and 1.25 times enhanced compared to that of TiO2 and TiO2/ZIS, respectively. Meanwhile, the incident photon-to-current conversion efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) of TiO2/ZIS/ZCIS were also increased in contrast with its counterparts. The merits of appropriate band alignment of TiO2, ZIS, and ZCIS and fewer interface defects built an internal electric field among the ternary hetero-junction, leading to an enhanced conductivity and efficient interface charge separation. These results were supported by a series of photo-electrochemical measurements. Among others, the shortened average lifetime of photo-generated electron-hole pairs from 1.51 (TiO2) to 1.17 ns (TiO2/ZIS/ZCIS) according to time-resolved photoluminescence reveals that the charge carriers generated in TiO2 would have an additional decay pathway in the hetero-structure, which benefits for the charge separation. Our strategy could be extended to many low-efficiency semiconductors for the design and synthesis of effective photo-anodes in PEC water splitting.

Covalent SO Bonding Enables Enhanced Photoelectrochemical Performance of Cu2 S/Fe2 O3 Heterojunction for Water Splitting.

The severe charge recombination and the sluggish kinetic for oxygen evolution reaction have largely limited the application of hematite (α-Fe2 O3 ) for water splitting. Herein, the construction of Cu2 S/Fe2 O3 heterojunction and discover that the formation of covalent SO bonds between Cu2 S and Fe2 O3 can significantly improve the photoelectrochemical performance and stability for water splitting is reported. Compared with bare Fe2 O3 , the heterostructure of Cu2 S/Fe2 O3 endows the resulting electrode with enhanced charge separation and transfer, extended range for light absorption, and reduced charge recombination rate. Additionally, due to the photothermal properties of Cu2 S, the heterostructure exhibits locally a higher temperature under illumination, profitable for increasing the rate of oxygen evolution reaction. Consequently, the photocurrent density of the heterostructure is enhanced by 177% to be 1.19mA cm-2 at 1.23V versus reversible hydrogen electrode. This work may provide guideline for future in the design and fabrication of highly efficient photoelectrodes for various reactions.

Co-catalytic effects of Bi-based metal-organic framework on BiVO4 photoanodes for photoelectrochemical water oxidation

Metal-organic frameworks (MOFs) are promising co-catalysts for increasingenhancing the performance of photoelectrochemical (PEC) water splitting. In this work, we successfully fabricated an efficient BiVO4 photoanode for PEC water oxidation by decorating its surface with Bi-based MOF as a co-catalyst via an unconventional immersion process at an ambient temperature. Bi-MOF exhibits a large surface area and promotes bulk charge separation and surface charge transfer in the water oxidation reaction, resulting in an enhancement in the photocurrent density, which is approximately two times larger than that of the bare BiVO4 photoanode. In addition, the operation stability of our Bi-MOF/BiVO4 photoanode was dramatically improved, and more than 95% of its initial photocurrent density was retained even after 24 h, indicating that the improved charge transfer by the Bi-MOF layer prohibits the dissolution of the BiVO4 layer into the solution during the water oxidation reaction.

Three-dimensional nanoporous SnO2/CdS heterojunction for high-performance photoelectrochemical water splitting

The porous structure is one of the effective structures to improve the photoelectrochemical (PEC) performance due to its high surface area to volume ratio. In this study, a porous carbon black (CB) film was prepared by a simple and inexpensive flame method, which was used as a template to grow three-dimensional (3D) nanoporous SnO2 through the atomic layer deposition (ALD) method, followed by CdS thin film coating. The photocurrent density of the optimized 3D nanoporous SnO2/CdS heterojunction (11.56 mA/cm2, 1.23 V vs. RHE) shows 9.7 times higher than that of planar SnO2/CdS film (1.20 mA/cm2, 1.23 V vs. RHE), meanwhile, the photocurrent stability was also 2.2 times improved. The maximum incident photon-to-current conversion efficiency (IPCE) and applied bias photo-to-current efficiency (ABPE) values of 35% (around 490 nm at 0 V vs. RHE) and 1.85% (at 0.90 V vs. RHE) were observed for the nanoporous SnO2/CdS. Furthermore, the surface charge separation and bulk charge transfer efficiencies have been achieved by 45.4% and 98.8% (1.23 V vs. RHE). As a whole, the results indicated that the 3D nanoporous SnO2/CdS heterojunction has been demonstrated as an efficient strategy that has been realized to show high performance in PEC water splitting.

Effect of noble metal ions dopants on solar photoelectrochemical water splitting and electrochemical supercapacitive performance of BiVO4 hollow tubes

Owing to their poor electrochemical properties, photoelectrochemical (PEC) solar water splitting and electrochemical energy storage activity of BiVO4 are presently limited in their applications. One of the effective methods for improving electrochemical activity is the doping of noble-metal ions into the host lattice. The doping of noble-metal ions can improve absorption in visible light and support the direct transfer of energy via hot electrons. In this study, the synthesis of Au-doped BiVO4 nanostructured catalysts with different concentrations of Au ions was prepared via a template-free ultrasonication technique, and it's both solar-driven PEC water splitting and electrochemical storage properties were examined. The optimal doped photoelectrode exhibited a lower resistance to charge transfer than other photoelectrodes, including a significant enhancement in photocurrent density (0.102 mAcm−2), which is approximately 4.1 times superior over undoped photoanode. Furthermore, the optimal doped electrode exhibited an electrochemical capacitance that is 2 times greater than that of the pure electrode. The excellent electrochemical behavior and PEC properties of the optimal doped electrode were attributed to the increase in surface area and suitable band gap. Consequently, enables the dispersion of electron at the interface of electrode/electrolyte. Solar PEC solar water splitting and supercapacitor performance of the optimal doped electrodes were significantly improved by the proper incorporation of Au ions.

In Situ Synthesis of α-Fe2O3/Fe3O4 Heterojunction Photoanode via Fast Flame Annealing for Enhanced Charge Separation and Water Oxidation.

Hematite (α-Fe2O3) is a promising photoanode material in photoelectrochemical (PEC) water splitting. To further improve the catalytic activity, a reasonable construction of heterojunction and surface engineering can effectively improve the photoanode PEC water-splitting performance via improving bulk carrier transport and interfacial charge-transfer efficiency. As Fe3O4 has an excellent conductivity and a suitable energy band position, α-Fe2O3/Fe3O4 heterojunction can be an ideal structure to improve the activity of α-Fe2O3. However, only few studies have been reported on α-Fe2O3/Fe3O4 heterojunctions as photoanodes. In this work, a holey nanorod Fe2O3/Fe3O4 heterojunction photoanode with oxygen vacancies was fabricated using a rapid and facile flame reduction treatment. Compared with pure Fe2O3, the water oxidation performance of the Fe2O3/Fe3O4 photoanode is improved by ninefold at 1.23 VRHE. Our study revealed that the porous nanorod structure providing more active sites and oxygen vacancies as the hole transfer medium, together improve the interface charge transfer performance of the photoanode. At the same time, Fe3O4 can form a Fe2O3/Fe3O4 heterojunction to improve the carrier separation efficiency. More importantly, Fe3O4 can serve as active sites, solving the slow water oxidation kinetic problem of hematite to enhance the catalytic activity. Our work shows that when flame acts on precursors containing oxygen or hydroxide, it is easy to form compounds with different microstructures or compositions in situ.

Improvement in the photoelectrochemical water-splitting performance using GaN nanowires with bundle structures

Improvement in the photoelectrochemical water splitting performance by reducing surface-trap states by forming bundle structures of GaN nanowires.

Controlling the carrier density in niobium oxynitride BaNbO2N via cation doping for efficient photoelectrochemical water splitting under visible light

Lower-valent cation doping enables appropriate reduction of undesirably high donor density in BaNbO2N, providing both a suitable electron conductivity and hole diffusion length with high photoelectrochemical performance for water splitting.

A significant enhancement of bulk charge separation in photoelectrocatalysis by ferroelectric polarization induced in CdS/BaTiO3 nanowires.

Efficient charge separation, in particular bulk charge separation (BCS), is one of the most critical factors in determining the performance of photoelectrochemical (PEC) water-splitting. The BCS enhancement of CdS/BaTiO3 (CdS/BTO) nanowires (NWs) in photoelectrocatalysis has rarely been reported. This paper describes a remarkable PEC properties promotion of the CdS/BTO NWs, which is confirmed to be a result of the enhanced BCS efficiency induced by the ferroelectric polarization. The vertical arrays of BTO NWs endow fast transfer of carriers. Meanwhile, CdS is decorated uniformly on the surface of BTO NWs, which ensures a wide range of light absorption. After two negative polarizations, the CdS/BTO NWs have successfully obtained a remarkable photocurrent density, achieving 459.53 μA cm−2 at 1.2 V(vs.RHE), which is 2.86 times that of the unpolarized sample. However, after two positive polarizations, the photocurrent density dramatically decreases to 40.18 μA cm−2 at 1.2 V(vs.RHE), which is merely 0.25 times the original value. More importantly, the photocurrent density reaches up to a prominent value of −71.09 mA cm−2 at −0.8 V(vs.RHE) after two successive negative polarizations, which is a 40.87 mA cm−2 enhancement with respect to the sample without poling. Significantly, at −0.8 V(vs.RHE), the BCS efficiency of the CdS/BTO NWs is as high as 91.87% after two negative polarizations. The effects of ferroelectric polarization on the PEC performance of CdS/BTO NWs have been systematically studied. The results demonstrate that ferroelectric polarization, especially negative polarization, results in an internal electric field to tune band bending of CdS/BTO NWs, thus prominently enhancing the PEC performance.

Visible Light-Driven Photoelectrocatalytic Water Splitting Using Z-Scheme Ag-Decorated MoS2/RGO/NiWO4 Heterostructure

Herein, we have successfully constructed a solid-state Z-scheme photosystem with enhanced light absorption capacity by combining the optoelectrical properties of AgNPs with those of the MoS2/RGO/NiWO4 (Ag-MRGON) heterostructure. The Ag-MRGON Z-scheme system demonstrates improved photo-electrochemical (PEC) water-splitting performance in terms of applied bias photon-to-current conversion efficiency (ABPE), which is 0.52%, and 17.3- and 4.3-times better than those of pristine MoS2 and MoS2/NiWO4 photoanodes, respectively. The application of AgNPs as an optical property enhancer and RGO as an electron mediator improved the photocurrent density of Ag-MRGON to 3.5 mA/cm2 and suppressed the charge recombination to attain the photostability of ∼2 h. Moreover, the photocurrent onset potential of the Ag-MRGON heterojunction (i.e., 0.61 VRHE) is cathodically shifted compared to those of NiWO4 (0.83 VRHE), MoS2 (0.80 VRHE), and MoS2/NiWO4 heterojunction (0.73 VRHE). The improved PEC water-splitting performance in terms of ABPE, photocurrent density, and onset potential is attributed to the facilitated charge transfer through the RGO mediator, the plasmonic effect of AgNPs, and the proper energy band alignments with the thermodynamic potentials of hydrogen and oxygen evolution.

Photoelectrochemical Water Splitting by In2S3/In2O3 Composite Nanopyramids

Photoelectrochemical (PEC) water-splitting reaction becomes an important path for the requirement of the fulfillment of global energy demand. For PEC water-splitting reactions, here In2O3 is grown in situ in the nanopyramidal structure of In2S3 via a simple hydrothermal technique. The limited supply of S2– in the reaction medium plays an important role in the development of In2O3 along with In2S3, leading to the In2S3/In2O3 nanocomposite. The In2S3/In2O3 nanocomposite shows an enriched carrier density compared to bare In2S3. The optimum amount of In2O3 in the composite helps to achieve efficient photoactivity. In addition, the observed negative shift of the flat band potential of the nanocomposite demonstrates the assistance of the early onset potential. Moreover, the In2S3/In2O3 nanocomposite shows improved visible light absorbance due to its pyramidal nanostructure. It can generate a high photoconversion efficiency of ∼0.55% at 0.77 V versus the reversible hydrogen electrode (RHE) in 0.5 M Na2SO4. The stability of the In2S3/In2O3 nanopyramid is determined under chopped illumination condition for 1000 s, which shows decay in the stability in the Na2SO4 medium. Importantly, to widen the applicability of the In2S3/In2O3 composite, the PEC water-splitting performance is determined in 3.5% saline water. Under such a corrosive environment, In2S3/In2O3 can show efficient photoactivity as well as outstanding stability. It can generate a photocurrent density of 0.83 mA/cm2 under an applied potential of 1.18 V versus the RHE. The present research suggests the development of the In2S3/In2O3 nanopyramid composite as a chloride environment-withstanding and high corrosion-resistant photoanode. The advantage of the faceted nanopyramidal structure and the composite is focused here. It paves an avenue for the development and engineering of highly persistent seawater-splitting photoelectrodes, which provides an opportunity to use the vast seawater on the Earth as an energy carrier.

Controllable low-temperature growth and enhanced photoelectrochemical water splitting of vertical SnS2 nanosheets on graphene

Two-dimensional (2D) SnS2 nanosheets vertically grown on graphene electrodes have still not been demonstrated despite their considerable research interest and potential for photoelectrochemical (PEC) applications. Herein, the controllable growth and enhanced PEC water-splitting performance of vertically aligned 2D SnS2 nanosheets on graphene are reported. The heterojunction quality of the graphene/2D SnS2 nanosheets was ensured by low-temperature growth at 230 °C using metalorganic chemical vapor deposition, resulting in significantly improved charge transfer properties. The PEC photocurrent density and photoconversion efficiency significantly increased upon insertion of a graphene layer. In addition, the 2D SnS2 nanosheet microscopic structure dependency of the PEC performance was systematically studied. The best PEC reactivity of the 2D SnS2 nanosheets was achieved at a height of ∼0.85 µm, corresponding to nearly the limit of the carrier diffusion length, and a thickness of ∼70 nm to balance the low interfacial contact resistance with an effective photogenerated carrier dynamics. These results, including the low-temperature vertical growth of 2D SnS2 on graphene, can effectively be utilized to exploit the full potential of 2D SnS2 for various PEC applications.

Chemical vapor deposition of amorphous molybdenum sulphide on black phosphorus for photoelectrochemical water splitting

Non-precious metal electrocatalyst molybdenum sulphide (MoS) and black phosphorus (BP) are highly promising catalysts for H2 evolution reaction (HER). However, BP is environmentally unstable and the basal planes of crystal MoS2 are inactive toward HER. Herein, amorphous molybdenum sulphide (MoSx) directly on BP/BiVO4 film dramatically improves the performance of photoelectrochemical water splitting compared with pure BiVO4. Additionally, we demonstrate that a BP layer, inserted between the MoSx and BiVO4, can enhance the photoelectrochemical performance and improve the stability of the electrodes. Finally, MoSx/BP/BVO electrode shows the excellent current density of 2.1 mA/cm2 at the potential of 1.2 V (vs Ag/AgCl), which is twice higher than that of pure BVO electrode. Our novel nanostructure materials will lead to a new class of non-precious metal photocatalysts for hydrogen production.

Modified synthesis of BiVO4 and effect of doping (Mo or W) on its photoelectrochemical performance for water splitting

The photoelectrochemical (PEC) water splitting approach is an interesting concept due to abundant solar energy source and economical viability. However, it is challenging to realize the theoretical potential of photoactive materials mainly because of intricate interactions between sunlight, semiconductors and liquid solutions. BiVO4 is one such promising material because of its favorable valence and conduction band position with a bandgap of ∼2.4 eV. In this work, thin films of BiVO4 (2 cm X 2 cm surface area) have been prepared through modified synthesis route by using robust USP technique. Further, BiVO4 doped with Mo or W elements of different atomic concentrations (3, 5, 7 and 9 at.%) have been prepared. The results indicate that doping of Mo and W in BiVO4 shown ∼2.5 times of higher photocurrent density as compared to pristine BiVO4. Poor electron–hole separation yield is one of the main limiting factors for BiVO4. The purpose of Mo or W-doping in this study is to increase the electron–hole separation yield which is resulted by improving the electron transport properties. Mo or W played a role of donor dopants by compensating cation vacancies or electrons, which contribute to increase in conductivity. Both structural and performance characterization of electrodes have been carried out to corroborate with the results. Increase in charge carrier density and decrease in charge transfer resistance unfolds the reason behind increase in photoelectrochemical performance.

3D-nano-hetero-structured n/n junction, CuO/Ru–ZnO thin films, for hydrogen generation with enhanced photoelectrochemical performances

Hydrogen, derived from solar-water splitting, is a clean and renewable fuel for which per gram energy storage capacity is even higher than fossil fuels. Towards the development of a viable technology for above conversion, this report describes enhanced performance in photoelectrochemical water splitting using uniquely evolved nano-hetero-structured bilayered thin films, CuO/Ru–ZnO as photoanode. Grown over ITO (In:SnO2) glass substrates by using low-cost and easily up-scalable wet chemical methods, films were characterized for microstructure, optical behaviour and surface characteristics, using XRD and other spectral measurements viz. FESEM, AFM, TEM, UV–Visible Spectroscopy, EDX and XPS. Against monolayered pristine films of CuO and ZnO, bilayered films yielded a major gain in PEC water splitting photocurrent, on being used as working electrode in PEC cell, in conjunction with platinum counter electrode and saturated calomel reference electrode (electrolyte solution 0.1 M NaOH solution, pH 13, temperature 30 ± 3.6 °C). Films with 1% Ru-incorporation yielded highest photocurrent (2.04 mA/cm2). Enhanced photoactivity of bilayered films was found correlated with increments in light absorption, charge carrier density and film surface area, coupled with reduced electrical resistivity. The study highlights an important role played by Ru added in ZnO overlayer, apparently existing as RuO2 nanoparticles dispersed in ZnO lattice, in hole-transfer from valence band of CuO underlayer to electrolyte, thereby imparting a significant boost on photocurrent generation.

Pulse laser annealing activates titanium-doped hematite photoanodes for photoelectrochemical water oxidation

Efficient activation of donor-type dopants is important for promoting the photoelectrochemical (PEC) performance of semiconductor photoanodes. High temperature annealing, the most often-adopted method, can active the dopants, but is accompanied by serious deterioration of the conductive substrate. Hence, it still remains a challenge to develop a new method to activate the dopants in semiconductor photoanodes deposited on a substrate that is not resistant to high temperature. Herein, we report a pulse laser annealing (PLA) strategy to activate titanium dopant in hematite photoanodes at room temperature to improve the PEC performance for water splitting. A short treatment with 450 nm nanosecond yttrium aluminum garnet (YAG) laser (20 pulses, 30 mJ cm−2 per pulse) causes crystallinity improvement and surface roughening of hematite photoanodes without destroying the fluorine doped SnO2 (FTO) conductive glass substrate, and results in a 1.85-fold increased photocurrent density (0.484 mA cm−2, 1.23 V vs. RHE) of Ti-doped hematite photoanodes (5% doping level, Ti:Fe2O3-PLA). The charge transfer efficiency at the surface of Ti:Fe2O3-PLA was approximately two-fold higher than Ti:Fe2O3, and a 10.1-fold increased donor density (1.29 × 1019 cm−3) was achieved, demonstrating the potential of PLA treatment for activating doped semiconductor photoanodes at room temperature.

Decorating non-noble metal plasmonic Al on a TiO2/Cu2O photoanode to boost performance in photoelectrochemical water splitting

Designing low-cost and high-performance photoelectrodes with improved light harvesting and charge separation rates is significant in photoelectrochemical water splitting. Here, a novel TiO2/Cu2O/Al/Al2O3 photoelectrode is manufactured by depositing plasmonic nanoparticles of the non-noble metal Al on the surface of a TiO2/Cu2O core/shell heterojunction for the first time. The Al nanoparticles, which exhibit a surface plasmon resonance (SPR) effect and are substantially less expensive than noble metals such as Au and Ag, generate hot electron–hole pairs and amplify the electromagnetic field at the interface under illumination. The as-prepared TiO2/Cu2O/Al/Al2O3 photoelectrodes have an extended absorption range and enhanced carrier separation and transfer. Their photocurrent density of 4.52 mA·cm−2 at 1.23 V vs. RHE represents an 1.84-fold improvement over that of TiO2/Cu2O. Specifically, the ultrathin Al2O3 passivation layer spontaneously generated on the surface of Al in air could act as a protective layer to significantly increase its stability. In this work, the synergistic effect of the heterojunctions and the SPR effect of the non-noble metal Al significantly improve the photoelectrode performance, providing a novel concept for the design of electrodes with good properties and high practicability.