Solar-driven overall water splitting is highly desirable for hydrogen generation with sustainable energy sources, which need efficient, earth-abundant, robust, and bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, we propose a heterogeneous bimetallic phosphide/sulfide nanocomposite electrocatalyst of NiFeSP on nickel foam (NiFeSP/NF), which shows superior electrocatalytic activity of low overpotentials of 91 mV at −10 mA cm–2 for HER and of 240 mV at 50 mA cm–2 for OER in 1 M KOH solution. In addition, the NiFeSP/NF presents excellent overall water splitting performance with a cell voltage as low as 1.58 V at a current density of 10 mA cm–2. Combining with a photovoltaic device of a Si solar cell or integrating into photoelectrochemical (PEC) systems, the bifunctional NiFeSP/NF electrocatalyst implements unassisted solar-driven water splitting with a solar-to-hydrogen conversion efficiency of ∼9.2% and significantly enhanced PEC performance, respectively.Keywords: electrochemistry; nanosheet; phosphosulfide; solar energy; water splitting;

The use of photoelectrochemical (PEC) sensors, with their outstanding advantages of remarkable sensitivity, inherent miniaturization, portability and easy integration, is becoming a promising analytical detection technique. The rational design of PEC materials and convenient establishment of PEC analysis platforms have given this technique tremendous popularity in both analytical and medical communities for biomolecule detection. However, most of the current efforts in the development of PEC analysis have been made with ultraviolet and visible light (UV-vis) as light source, which are detrimental to biomolecules because of their high energy. On the contrary, near-infrared (NIR) light is biocompatible and is available for in vivo detection. Herein, a prototype of NIR light-responsive PEC analysis platform is first proposed with defect-engineered TiO2 nanotube photonic crystals as photoelectrode and dopamine as target molecule. The coupled strategies of defect engineering for electronic structure modification and morphology design for photon manipulation open up a distinctive avenue to not only implement sensitive NIR PEC detection of dopamine but also have potential multi-target detection ability by integrating bio-recognition units, thus promoting NIR PEC analysis as a versatile analysis method.

In this communication, we report the first demonstration of an efficient photoelectrochemical aptasensor based on sputtering Au nanoparticle-modified nanoporous BiVO4 for the excellent sensitive and selective detection of thrombin with a low detection limit of 0.5 pM and a large linear range.

Carbon dioxide, CO2, is thought to be a main culprit leading to global climate change and a wide variety of strategies have been proposed to reduce atmospheric CO2 levels. Here, CO2 is captured and subsequently electrochemically split into carbon materials in an electrolyzer comprising a eutectic mixture of carbonates, an Fe cathode and a Ni anode, at 600 °C and current densities of 50, 100, 200 mA cm−2. SEM, EDS, XRD and BET are employed to analyze the morphology, elemental composition, crystal structure as well as the BET surface area of the synthetic cathodic products. In addition, coulomb efficiency under different electrolytic conditions is measured via the comparison between moles of formed carbon product and the Faradays of charge passed during the electrolysis reaction. This paper investigated the effect of molten carbonate compositions on carbon product generation, and confirmed the visible dependence of produced carbon on the electrolytes.

•A prototype of recognition biomolecule unit-free photoelectrochemical sensing platform was proposed.•The TiO2 nanotube photonic crystal material was used as photoelectrode.•The dopamine molecule was used as both sensitizer and target analyte.•The unique adsorption between dopamine and TiO2 nanotube photonic crystal induces the formation of charge transfer complex.•This simple photoelectrochemical analysis platform can be used for dopamine detection from mouse brain.For implementing sensitive and selective detection of biological molecules, the biosensors are been designed more and more complicated. The exploration of detection platform in a simple way without loss their sensitivity and selectivity is always a big challenge. Herein, a prototype of recognition biomolecule unit-free photoelectrochemical (PEC) sensing platform with self-cleaning activity is proposed with TiO2 nanotube photonic crystal (TiO2 NTPCs) materials as photoelectrode, and dopamine (DA) molecule as both sensitizer and target analyte. The unique adsorption between DA and TiO2 NTPCs induces the formation of charge transfer complex, which not only expends the optical absorption of TiO2 into visible light region, thus significantly boosts the PEC performance under illumination of visible light, but also implements the selective detection of DA on TiO2 photoelectrode. This simple but efficient PEC analysis platform presents a low detection limit of 0.15 nm for detection of DA, which allows to realize the sensitive and selective determination of DA release from the mouse brain for its practical application after coupled with a microdialysis probe. The DA functionalized TiO2 NTPCs PEC sensing platform opens up a new PEC detection model, without using extra-biomolecule auxiliary, just with target molecule naturally adsorbed on the electrode for sensitive and selective detection, and paves a new avenue for biosensors design with minimalism idea.

•A strategy is proposed to transform CO2/H2O into syngas with electrolysis method.•All energy consumption is contributed from sustainable energy sources.•Eutectic molten electrolyte is rationally designed with a low melting point.•The syngas contains H2 and CO with tuneable molar ratio from 0.6 to 7.8.Over-reliance on non-renewable fossil fuel leads to steadily increasing concentration of atmospheric CO2, which has been implicated as a critical factor contributing to global warming. The efficient conversion of CO2 into useful product is highly sought after both in academic and industry. Herein, a novel conversion strategy is proposed to one-step transform CO2/H2O into syngas (CO/H2) in molten salt with electrolysis method. All the energy consumption in this system are contributed from sustainable energy sources: concentrated solar light heats molten salt and solar cell supplies electricity for electrolysis. The eutectic Li0.85Na0.61K0.54CO3/nLiOH molten electrolyte is rationally designed with low melting point (<450 °C). The synthesized syngas contains very desirable content of H2 and CO, with tuneable molar ratios (H2/CO) from 0.6 to 7.8, and with an efficient faradaic efficiency of ∼94.5%. The synthesis of syngas from CO2 with renewable energy at a such low electrolytic temperature not only alleviates heat loss, mitigates system corrosion, and heightens operational safety, but also decreases the generation of methane, thus increases the yield of syngas, which is a remarkable technological breakthrough and this work thus represents a stride in sustainable conversion of CO2 to value-added product.Download high-res image (323KB)Download full-size image

In this communication, we report for the first time the demonstration of a lithium ion intercalation strategy to significantly enhance the photoelectrochemical water splitting performance on 3-dimensional vertical hierarchical top-porous-bottom-tubular TiO2 nanotubes on a fabricable titanium mesh.

Photoelectrochemical (PEC) water splitting is a promising technique for sustainable hydrogen generation. However, PEC performance on current semiconductors needs further improvement. Herein, a phosphorus cation doping strategy is proposed to fundamentally boost PEC performance on TiO2 nanotube photonic crystal (TiO2 NTPC) photoelectrodes in both the visible-light region and full solar-light illumination. The self-supported P-TiO2 NTPC photoelectrodes are fabricated by a facile two-step electrochemical anodization method and subsequent phosphidation treatment. The Ti4+ is partially replaced by P cations (P5+) from the crystal lattice, which narrows the band gap of TiO2 and induces charge imbalance by the formation of Ti–O–P bonds. We believe the combination of unique photonic nanostructures of TiO2 NTPCs and P cation doping strategy will open up a new opportunity for enhancing PEC performance of TiO2-based photoelectrodes.Keywords: phosphorus cation; photoelectrochemical water splitting; photonic crystal; TiO2 nanotube

In this work, we clearly demonstrate for the first time the use of transition-metal phosphides to set up a new cathodic analysis platform for sensitive and selective electrochemical nonenzymatic detection of H2O2. With the help of a facile topotactic conversion method, the noble metal-free electrocatalyst of copper(I) phosphide nanowires on three-dimensional porous copper foam (Cu3P NWs/CF) is fabricated with electrochemical anodized Cu(OH)2 NWs as precursor. The Cu3P NWs/CF-based sensor presents excellent electrocatalytic activity for H2O2 reduction with a detection limit of 2 nM, the lowest detection limit achieved by noble-metal free electrocatalyst, which guarantees the possibility of sensitive and reliable detection of H2O2 release from living tumorigenic cells, thus showing the potential application as a sensitive cancer cell detection probe.

Effective utilization of ultraviolet and visible light for hydrogen evolution in a photoelectrochemical (PEC) water splitting approach has been widely investigated, whereas infrared light, another major fraction of solar radiation (∼50%), is rarely reported for implementing PEC water splitting application. In this paper, we first demonstrate the coupling of air and solution stable pyrite iron disulfide (FeS2) with hierarchical top-porous–bottom-tubular TiO2 nanotubes (TiO2 NTs) to realize high PEC performance not only in the ultraviolet and visible light regions but also in the infrared light region with photocurrent enhancement by more than 3 orders of magnitude compared to that of the pristine TiO2 NTs under illumination of near-infrared light. The significant enhancement of PEC performance can be ascribed to the rational coupling of FeS2 with a small band gap and TiO2 NTs with unique morphology and proper electronic features. We postulate the proposed novel FeS2/TiO2 NTs photoelectrode has the potential to address the low efficiency of PEC water spitting in the infrared light region, and thus can make a significant contribution in the field of energy conversion.Keywords: FeS2; Infrared light; Photoelectrochemical; TiO2 nanotube; Water splitting;

In this communication, a new class of photonic materials, namely, two-dimensional titanium oxide-based photonic crystals, are proposed and were fabricated with an electrochemical anodization method. The high structural periodicity of the nanostructures, and the feasible variability of the chemical compositions help to realize tunable photonic bandgaps for selective light absorption in broad wavelength regions.

In this communication, a new photoelectrochemical aptasensor with Au nanoparticle functionalized self-doped TiO2 nanotube arrays (Au/SD-TiO2 NTs) as the core sensing unit and aptamers as the recognition unit was set up to accomplish the sensitive and selective detection of kanamycin with the lowest detection limit of 0.1 nM.

In this work, we clearly demonstrate for the first time the use of a p-type semiconductor, Cu2O, as the core unit of a photocathode to set up a new photocathodic analysis platform. With the help of a facile protection strategy, the Cu2O photocathode presented efficient photoelectrochemical performance for H2O2 sensing with a detection limit of 0.15 μM, which allowed the new photocathodic analysis platform to detect H2O2 released from living tumorigenic cells, thus demonstrating its potential application as a sensitive cancer detection probe. The protected TiO2 layer was coated on Cu2O to form a quasi-core/shell structure (TiO2@Cu2O) through a facile sol–gel method, which significantly enhanced the photostability, comparable to the TiO2@Cu2O samples prepared by a complicated atomic layer deposition method. In this new photocathodic analysis platform, the semiconductive metal oxides accomplish a job usually completed by conductive noble metals in an electroanalysis process. We believe that this photocathodic detection strategy opens up a new detection approach, extends the application range of semiconductor materials, and thus sheds light on the further fusing of photoelectrochemical technique with analytical methods.

In this paper, the honeycombed top-porous/bottom-tubular TiO2 nanotube arrays (TiO2 NTs) were prepared by a facile two-step anodization method. The structural parameters of honeycombed TiO2 NTs can be well controlled by adjusting the voltages in the second-step anodization process, and the honeycombed TiO2 NTs showed much enhanced photocatalytic activity than the conventional 1-step TiO2 NTs.

TiO2 based photonic materials (TiO2 PMs) with hierarchical top-nanonet/bottom-nanotube structures were fabricated by a facile two-step electrochemical anodization method. The TiO2 PMs demonstrated multiple band light trapping activity not only in the ultraviolet and visible regions, but also in the near infrared region.

In this communication, Pt nanoparticles (NPs) were successfully loaded on hierarchical TiO2 nanotube arrays (TiO2 NTs) for efficient decomposition of gas phase pollutants. The loading of Pt NPs on TiO2 NTs significantly enhanced the photocatalytic activity due to reduction of the recombination of photogenerated electrons and holes.

In this communication, we report for the first time the demonstration of a lithium ion intercalation strategy to significantly enhance the photoelectrochemical water splitting performance on 3-dimensional vertical hierarchical top-porous-bottom-tubular TiO2 nanotubes on a fabricable titanium mesh.

In this communication, a new photoelectrochemical aptasensor with Au nanoparticle functionalized self-doped TiO2 nanotube arrays (Au/SD-TiO2 NTs) as the core sensing unit and aptamers as the recognition unit was set up to accomplish the sensitive and selective detection of kanamycin with the lowest detection limit of 0.1 nM.

TiO2 based photonic materials (TiO2 PMs) with hierarchical top-nanonet/bottom-nanotube structures were fabricated by a facile two-step electrochemical anodization method. The TiO2 PMs demonstrated multiple band light trapping activity not only in the ultraviolet and visible regions, but also in the near infrared region.

The use of photoelectrochemical (PEC) sensors, with their outstanding advantages of remarkable sensitivity, inherent miniaturization, portability and easy integration, is becoming a promising analytical detection technique. The rational design of PEC materials and convenient establishment of PEC analysis platforms have given this technique tremendous popularity in both analytical and medical communities for biomolecule detection. However, most of the current efforts in the development of PEC analysis have been made with ultraviolet and visible light (UV-vis) as light source, which are detrimental to biomolecules because of their high energy. On the contrary, near-infrared (NIR) light is biocompatible and is available for in vivo detection. Herein, a prototype of NIR light-responsive PEC analysis platform is first proposed with defect-engineered TiO2 nanotube photonic crystals as photoelectrode and dopamine as target molecule. The coupled strategies of defect engineering for electronic structure modification and morphology design for photon manipulation open up a distinctive avenue to not only implement sensitive NIR PEC detection of dopamine but also have potential multi-target detection ability by integrating bio-recognition units, thus promoting NIR PEC analysis as a versatile analysis method.