Photo-assisted Zn-air batteries (PZABs) hold promise for advancing sustainable energy systems. Herein, to address challenges associated with the cathode charging oxygen evolution reaction (OER), a photo-assisted hybrid Zn-air battery (PHZAB) was constructed by employing photoelectrocatalytic glycerol oxidation reaction (GOR), which is thermodynamically favorable as a replacement for OER during the charging process. Based on element doping and cocatalyst loading strategies, the CoFe-LDH/Mo:BiVO4 photoanode was fabricated. Systematic photoelectrochemical tests demonstrate its excellent performance, with a GOR current density of 4.78 mA·cm−2 at 1.23 V vs. RHE, 2.6 times that of the BiVO4, and an applied bias photon-to-current efficiency (ABPE) of 2.21%, 3.7 times that of the BiVO4. Further analysis proves that these modification strategies enhance bulk carrier density, accelerate surface catalytic reactions, and effectively suppress carrier recombination, thus enhancing the photoelectrochemical (PEC) performance. Benefiting from the excellent performance of the CoFe-LDH/Mo:BiVO4 photoanode and the novel hybrid device structure design, the PHZAB exhibits a maximum round-trip efficiency of 206% (at 0.5 mA·cm−2) and a 68.7% electricity saving ratio under 1 sun illumination. Even at 2 mA·cm−2, a 156% round-trip efficiency and 64.2% electricity saving ratio were maintained. During the photoassisted-charging process, the optimized CoFe-LDH/Mo:BiVO4 photoanode yields a high GOR performance of a total production rate of 225 mmol·m−2·h−1 and formic acid (FA) production rate of 133 mmol·m−2·h−1. This work presents a novel bifunctional system toward the rational design of functional devices and materials for simultaneously converting solar energy into chemical energy and enabling reversible solar power storage for on-demand release.
- Article type
- Year
- Co-author
Open Access
Research Article
Issue
Open Access
Research Article
Issue
Photo-rechargeable batteries based on photocathodes that have the dual function of collecting and storing solar energy offer an efficient method for solar energy utilization. Herein, NiCo-layered double hydroxides (NiCo-LDH)/ZnIn2S4/carbon nanotubes (CNTs) (recorded as CZN), a heterostructure photocathode, has been synthesized by layer-by-layer growth for photo-driven rechargeable aqueous zinc batteries (AZBs). The proposed photocathode exhibits typical photoelectric properties and offers the following advantages: good photoresponse in the visible light range, energy level/potential matching between ZnIn2S4 and NiCo-LDH, and the conductive network formed by CNTs to promote charge transfer. The photo-driven rechargeable AZBs can harvest solar energy and store charge simultaneously, showing enhanced energy storage capability under illumination. The discharge capacity reaches 274.8 mAh·g−1 with a high photo-conversion efficiency of 1.120% at 8.0 A·g−1 (100 mW·cm−2, white light). In particular, the photo-driven rechargeable AZBs can be charged by light solely, achieving a discharge capacity of 116.3 mAh·g−1. This study shows that the novel design and synthesis of the heterostructure photocathode is crucial and significant to enhancing the practicality of solar energy.
High-entropy oxides receive significant attention owing to their “four effects”. However, they still suffer from harsh construction conditions such as high temperature and high pressure and present a block-like structure. Herein, in this work, Ni-Mn-Cu-Co-Fe-Al high-entropy layered oxides (HELOs) with a layered nanosheet structure were constructed by a simple pathway of topological transformation under relatively low temperature (300 °C) with six-membered Ni-Mn-Cu-Co-Fe-Al layered double hydroxides (LDHs) precursors, which exhibited an outstanding activity and excellent selectivity for CO2 photoelectroreduction (obtaining the highest carbon monoxide yield of 909.55 μmol·g−1·h−1 under −0.8 V vs. reversible hydrogen electrode (RHE), which is almost twice that of pure electrocatalysis). In addition, the charging voltage of a photo-assisted Zn-CO2 battery with HELOs as electrode was reduced from 2.62 to 2.40 V; the discharging voltage of the battery was increased from 0.51 to 0.59 V with the assistance of illumination. The improvement of round-trip efficiency of the battery indicates that light played a positive role in both the charging and discharging processes. This study not only lays an important foundation for the development of high-entropy oxides but also expands their application in the field of photoelectrochemistry.
Oxygen reduction reaction (ORR) plays a pivotal role in advanced electrochemical energy conversion devices. However, the ORR conversion efficiency is extremely limited. The major obstacles originate from the adsorption and activation of O2 on the electrode surface. A novel nanocomposite catalyst, photosensitizers (PS) meso-tetraphenylporphyrin iron(III) chloride (FePcCl)/NiCoFe-layered double hydroxides (NiCoFe-LDHs) is designed in this study. Herein, owing to excellent oxygen molecules activation ability and remarkable illumination absorption feature, FePcCl/NiCoFe-LDHs is employed to uncover the relationship between the intrinsic ORR activity and PS behaviour. Interestingly, the reaction mechanism of singlet 1O2 is proposed owing to the combination of electrochemical ORR catalysed via LDHs and PS. The boosted cathodic ORR properties exhibit singlet 1O2 dependent response arising from the synergistic effect to selectively produce active intermediates in alkaline medium. This work imparts the promising new mechanism about the high 4-electron ORR selectivity via material design, which will guide the development of photo-assisted energy conversion devices.
In contrast to reactive oxygen species (ROS), the generation of oxygen-irrelevant free radicals is oxygen- and H2O2-independent in cell, which can offer novel opportunities to maximum the chemodynamic therapy (CDT) efficacy. Herein, an H2O2-independent “functional reversion” strategy based on tumor microenvironment (TME)-toggled C-free radical generation for CDT is developed by confining astaxanthin (ATX) on the NiFe-layered double hydroxide (LDH) nanosheets (denoted as ATX/LDH). The unique ATX/LDH can demonstrate outstanding TME-responsive C-free radical generation performance by proton coupled electron transfer (PCET), owing to the specific ATX activation by unsaturated Fe sites on the LDH nanosheets formed under TME. Significantly, the Brönsted base sites of LDH hydroxide layers can promote the generation of neutral ATX C-free radicals by capturing the protons generated in the ATX activation process. Conversely, ATX/LDH maintain antioxidant performance to prevent normal tissue cancerization due to the synergy of LDH nanosheets and antioxidative ATX. In addition, C-free radical can compromise the antioxidant defense in cells to the maximum extent, compared with ROS. The free radicals burst under TME can significantly elevate free radical stress and induce cancer cell apoptosis. This strategy can realize TME-toggled C free radical generation and perform free radical stress enhanced CDT.
Ammonia is important for industrial development and human life. The traditional Haber Bosch method converts nitrogen into ammonia gas at high temperatures and pressures, causing serious pollution and greenhouse gas emissions. These problems prompt the nitrogen fixation method to proceed in a sustainable way. Ultrathin Ni/V-layered double hydroxides (Ni/V-LDHs) nanosheets with different proportions were prepared successfully for photocatalystic reduction of nitrogen to ammonia, through aqueous miscible organic solvent method (AMO) to achieve the higher surface area and rich oxygen vacancies, containing more carriers and active sites to enhance nitrogen reduction. And the optimal catalyst of Ni/V-LDHs 11 AMO possesses the highest photocatalytic efficiency (176 µmol·g−1·h−1), indicating its potential application prospects in catalyst fields. Consequently, this work achieves an environmentally friendly, low-cost and efficient conversion method for nitrogen reduction to ammonia through solar energy.
Lithium-sulfur batteries are promising electrochemical energy storage devices because of their high theoretical specific capacity and energy density. An ideal sulfur host should possess high conductivity and embrace the physical confinement or strong chemisorption to dramatically suppress the polysulfide dissolution. Herein, uniform TiN hollow nanospheres with an average diameter of ~160 nm have been reported as highly efficient lithium polysulfide reservoirs for high-performance lithium-sulfur batteries. Combining the high conductivity and chemical trapping of lithium polysulfides, the obtained S/TiN cathode of 70 wt.% sulfur content in the composite delivered an excellent long-life cycling performance at 0.5C and 1.0C over 300 cycles. More importantly, a stable capacity of 710.4 mAh·g?1 could be maintained even after 100 cycles at 0.2C with a high sulfur loading of 3.6 mg·cm?1. The nature of the interactions between TiN and lithium polysulfide species was investigated by X-ray photoelectron spectroscopy studies. Theoretical calculations were also carried out and the results revealed a strong binding between TiN and the lithium polysulfide species. It is expected that this class of conductive and polar materials would pave a new way for the high-energy lithium-sulfur batteries in the future.
京公网安备11010802044758号