3D PD Research Articles

Ternary gallide Zr7Pd7–xGa3+x (0 ≤ x ≤ 1.8): Synthesis, crystal and electronic structures

The new ternary compound Zr7Pd7-xGa3+x (0 ≤ x ≤ 1.8) was synthesized by arc melting the elements under argon and subsequent annealing the ingots at 870 K for 720 h. The polycrystalline samples were characterized by powder X-ray diffraction (XRD) and the crystal structure of the compound was determined from single crystal X-ray diffraction data. Zr7Pd7Ga3 crystallizes with a ternary version of the Zr7Ni10 type of structure exhibiting statistical mixtures of palladium and gallium atoms on three crystallographically independent nickel sites (oS68, Cmce, a = 12.997(3), b = 9.623(2), c = 9.630(2) Ǻ, Z = 4, R1 = 0.033, wR2 = 0.067 for 719 unique reflections with Io> 2σ(Io) and 48 refined parameters). The crystal structure of Zr7Pd7Ga3 is represented by a 3D Pd–Ga framework built of sinusoidal layers of Pd and Ga stacking along the b axis sandwiching the Zr atoms. The homogeneity range of the compound Zr7Pd7–xGa3+x has been refined from powder XRD and EDX data: 0 ≤ x ≤ 1.8; variation of the lattice parameters is the following: a = 13.0174(8)–12.904(3), b = 9.6306(8)–9.559(8), c = 9.6348(8)–9.700(5) Å. Electronic structure calculations have been performed for an idealized model Zr7Pd10 as well as a model compound Zr7Pd6.5Ga3.5 revealing that the Ga-free Zr7Pd10 is significantly destabilized by strong Pd–Pd anti-bonding interactions. Substitution of Pd by Ga reduces those, stabilizing Zr7(Pd,Ga)10 which features strong heteroatomic bonding between Zr and the Pd/Ga substructure, putting it into the class of polar intermetallics.

Freestanding Penta-Twinned Palladium Nanosheets.

Control over the morphology of nanomaterials to have a 2D structure and manipulating the surface strain of nanostructures through defect control have proved to be promising for developing efficient catalysts for sustainable chemical and energy conversion. Here a one-pot aqueous synthesis route of freestanding Pd nanosheets with a penta-twinned structure (PdPT NSs) is presented. The generation of the penta-twinned nanosheet structure can be succeeded by directing the anisotropic growth of Pd under the controlled reduction kinetics of Pd precursors. Experimental and computational investigations showed that the surface atoms of the PdPT NSs are effectively under a compressive environment due to the strain imposed by their twin boundary defects. Due to the twin boundary-induced surface strain as well as the 2D structure of the PdPT NSs, they exhibited highly enhanced electrocatalytic activity for oxygen reduction reaction compared to Pd nanosheets without a twin boundary, 3D Pd nanocrystals, and commercial Pd/C and Pt/C catalysts.

(113) A Novel 3D Cellular Model for Peyronie's Disease Treatment Screening: PD.SPHERE

Abstract Introduction Peyronie's disease (PD) is a common issue that affects approximately 10% of males. Currently, researchers primarily study the pathogenesis and potential treatments for PD using monolayer fibroblast cells and a limited number of animal models. However, these models do not accurately represent the complex cellular structure and interactions involved in PD pathogenesis. We have successfully developed a three-dimensional (3D) cellular model, called PD.SPHERE, using a ground-breaking 'micro-gravity' cell culture method. This model is cultivated from extracted human PD tissues and serves as a valuable tool for in vitro treatment screening for PD. However, we have yet to use this model to evaluate the effectiveness of available and potential treatments. Objective Our objective is to determine the efficacy of the novel 3D cellular PD model, PD.SPHERE, as a treatment screening tool. Methods To achieve this, we cultured fibroblasts isolated from human PD tissues using the 'micro-gravity' approach. In this method, cells were seeded in a non-adhesive 96-well plate, placed on an orbital shaker, and incubated at 37°C with 5% CO2 and 95% relative humidity. We confirmed the proper morphology and cellular composition through microscopic assays. This 3D model was then used to assess the effects of collagenase clostridium histolyticum (CCH) and the actinidin enzyme, obtained from kiwi fruits. The PD.SPHERE was treated with actinidin at 10 mg/ml for 48 hours. We subsequently quantified collagen content using a soluble collagen quantification kit and observed viability, morphology, and changes in cellular compositions of the spheroids through immunofluorescent techniques and confocal microscopy. Results Preliminary results from our model have indicated significant changes in cellular morphology. Treatment with actinidin led to a significant decrease in spheroid size and density compared to the control group (P<0.01). The ratio of vimentin and actin filaments to nuclei staining was slightly but significantly reduced (P<0.05) in the spheroids treated with actinidin at 10 mg/ml. The cellular viability of the treated group showed a slight decrease, as revealed by Sytox Green staining. The assessment of collagen contents in the treated spheroids is ongoing. Conclusions Preliminary results suggest that our PD.SPHERE model can be effectively used to assess morphological and cellular component changes in PD tissues after treatment. Actinidin appears to compromise the plasma membrane of fibroblasts in PD.SPHERE. Our model holds promise for personalized treatment planning and potential for developing high-throughput treatment screening platforms. It also demonstrates consistency and reproducibility while closely mimicking the morphology of a PD plaque. Further research is required to collect signature gene expression data, physiological and immunological information, such as collagen production, extracellular matrix organization, and cellular expression of tight junctions, chemokines, and cytokines. These additional measures will help verify our model's pathophysiological, immunological, and treatment response aspects. Disclosure No.

A rapid response room temperature hydrogen sensor based on a three-dimensional Pd–In2O3/rGO aerogel

A three-dimensional (3D) Pd–In2O3/rGO aerogel was fabricated via a one-step hydrothermal treatment and freeze-drying.

Controllable synthesis of porous 3D Pd loaded ZIF-67/g-C3N4 hierarchical nanostructure for efficient detection of NO2 gas at room temperature

The two-dimensional (2D) g-C3N4 nanosheets have been widely recognized for their great potential in gas sensing. However, the disadvantages brought by layer stacking of two-dimensional nanosheets also seriously affect their performance and application. In this paper, three-dimensional hydrangea-like Pd-ZIF-67/g-C3N4 was prepared for the detection of nitrogen dioxide gas at room temperature via a simple hydrothermal method. The Pd-ZIF-67/g-C3N4 gas sensor exhibited excellent sensing properties with highest sensing response (23.8–100 ppm), ultrafast response speed (0.5 s) and lowest limit of detection (10 ppb) at room temperature. Moreover, it also manifests excellent reversibility and durability, optimal stability and commendable selectivity towards NO2 gas. This excellent performance is due to the three-dimensional spatial configuration, synergistic effect and catalytic action of Pd. In general, the constructed structure and the proposed design strategy have a certain promoting role in promoting the creation of high performance gas sensors with three-dimensional heterogeneous structures based on two-dimensional nanosheets.

Pd as a reduction promoter for TiO2: Oxygen and hydrogen transport at 2D and 3D Pd interfaces with TiO2 monitored by TPR, operando1H NMR and CO oxidation studies

Ambient temperature reduction of TiO2 surface was observed through hydrogen spillover from Pd nanoparticles with a hydrogen consumption stoichiometry of 1.4 H2:Pd up to ≤2 wt%Pd loading. This behavior was attributed to the formation of nanoparticles exhibiting 2D behavior for ≤2 wt%Pd loading. The 2D behavior of Pd nanoparticles were further confirmed from the relative abundance of metallic Pd in 3D, deduced from hydrogen stoichiometry of β-PdHx. EPR revealed oxygen vacancy formation, operando NMR revealed facile hydrogen spillover, and CO oxidation reaction rates systematically increased for Pd ≤ 2 wt%, indicating facile exchange of hydrogen and oxygen at 2D Pd/TiO2 interfaces.

Engineering three-dimensional superstructure of Pd aerogel with enhanced performance for ethanol electrooxidation

• Pd aerogel illustrates great electrocatalytic activity and durability toward ethanol oxidation reaction. • Pd aerogel was prepared through drying Pd hydrogel by supercritical CO 2. • One-pot and eco-friendly synthesis method for the generation of Pd aerogel assembled by nanochaines. A new, straightforward, and one-step method to synthesize self-supported three-dimensional (3D) Pd aerogel utilizing formaldehyde as a reducing agent in an alkaline medium was introduced for the first time in this research. The physicochemical properties investigation of Pd aerogel was conducted using x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) analyses. The electrocatalytic activity of prepared self-assembled nanoarchitecture toward ethanol electrooxidation was examined utilizing cyclic voltammetry (CV) and chronoamperometry (CA). The Pd aerogel on account of the unique morphology and numerous open interconnected pores revealed superior electrocatalytic activity (1016 mAmg -1 pd ) and enhanced durability toward ethanol electrooxidation in comparison to Pd/C nanocatalyst (281 mAmg -1 pd ). The larger electrochemical active surface area of the Pd aerogel catalyst (79.14 m 2 g −1 ) led to a boost in current density in the electrooxidation of ethanol in comparison to the Pd/C catalyst (12.34 m 2 g −1 ). We believe that our unique method can be used as a fast and powerful method for the synthesis of used catalysts in various energy-related systems.

Unique superstructure of Pd–Ir aerogel as a robust three-dimensional electrocatalyst

Herein, a novel, facile, fast, and one-step strategy is introduced to synthesize a three-dimensional (3D) Pd–Ir aerogel. The Pd–Ir aerogel is synthesized by reducing metallic ions in the presence of sodium carbonate and formaldehyde, followed by CO2 supercritical drying. Controlling the type of generated nanostructures and the reaction kinetics is adjusted by the sodium carbonate concentration. The change of sodium carbonate concentration is employed for creating an efficient anisotropic condition to create a Pd–Ir aerogel. The aerogel depicts a 3D architecture with a large porosity and an ultra-low density (0.022 g cm−3). This unique architecture illustrates the exceptional electrocatalytic activity and durability owing to the following vital reasons. The 3D architecture with large open pores not only significantly facilitates the accessibility of ethanol molecules to inner active sites but also guarantees the interaction of ethanol molecules with the surface of aerogel. Furthermore, the downfall of durability observed in the Pd/C owing to corrosion can eliminate by the self-supported nature of assembled aerogel. Moreover, the presence of Ir in the structure of aerogel leads to an alteration in the electronic structure of palladium, which facilitates the electrooxidation of ethanol at a high pH environment.

Pd homojunctions enable remarkable CO2 electroreduction.

3D Pd aerogels with a controllable homojunction density are synthesized using an innovative melting-casting technology. The homojunction-rich Pd aerogels selectively reduce CO2 to CO with a 92.3% faradaic efficiency and durability over 10 h, benefiting from the strong coupling between the electrons and the adsorbed intermediates at the phase-mismatch interface.

Hierarchical Pd and Pt structures obtained on 3D carbon electrodes as electrocatalysts for the ethylene glycol electro-oxidation

The heterogeneous surface of three-dimensional (3D) nanomaterials allows to increase the electrocatalytic activity for alcohols oxidation due to the presence of surface defects with high reactivity. In this work, 3D Pd and Pt materials were synthesized through electrodeposition directly on 3D tubular carbon porous electrodes (labeled as Pd/3D-C and Pt/3D-C) and then, used as electrocatalysts for the ethylene glycol electro-oxidation reaction (EGOR). Pd/3D-C was found in form of a hierarchical growth of Pd branched particles (∼28.5 nm) with missing rows, while Pt was in form of a thin film composed by sub <20 nm rosette-like 3D nanoparticles (∼11.5 nm). Thermogravimetric curves indicated that metal loadings of 134.56 and 198.37 μg cm−2 were achieved by electrodeposition for Pd/3D-C and Pt/3D-C. The chemical surface analysis performed by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy revealed that the surface atomic % of Pt was 4.9/4.4 higher to that of Pd, which was attributed to the difference in particle size/shape and surface coverage. The electrocatalytic tests indicated that both materials had an activity trend of 0.5 M KOH > 0.5 M NaOH > 0.5 M LiOH > 0.5 M H2SO4. After optimization of parameters like the KOH and EG concentration, Pd/3D-C and Pt/3D-C displayed overpotentials of 390 and 320 mV from the difference between the thermodynamic potential (0.11 V vs. RHE) and the onset potentials. Additionally, the current density was always higher in Pd/3D-C indicating a higher reactivity of its active sites. The stability tests revealed that Pd/3D-C maintained the active surface area (77.56 vs. 49.93%) and activity (112.04 vs. 39.48%) after 500 cycles in comparison with Pt/3D-C.

A 10-Year Retrospective Review of Prenatal Applications, Current Challenges and Future Prospects of Three-Dimensional Sonoangiography.

Realistic reconstruction of angioarchitecture within the morphological landmark with three-dimensional sonoangiography (three-dimensional power Doppler; 3D PD) may augment standard prenatal ultrasound and Doppler assessments. This study aimed to (a) present a technical overview, (b) determine additional advantages, (c) identify current challenges, and (d) predict trajectories of 3D PD for prenatal assessments. PubMed and Scopus databases for the last decade were searched. Although 307 publications addressed our objectives, their heterogeneity was too broad for statistical analyses. Important findings are therefore presented in descriptive format and supplemented with the authors’ 3D PD images. Acquisition, analysis, and display techniques need to be personalized to improve the quality of flow-volume data. While 3D PD indices of the first-trimester placenta may improve the prediction of preeclampsia, research is needed to standardize the measurement protocol. In highly experienced hands, the unique 3D PD findings improve the diagnostic accuracy of placenta accreta spectrum. A lack of quality assurance is the central challenge to incorporating 3D PD in prenatal care. Machine learning may broaden clinical translations of prenatal 3D PD. Due to its operator dependency, 3D PD has low reproducibility. Until standardization and quality assurance protocols are established, its use as a stand-alone clinical or research tool cannot be recommended.

3D Taraxacum-like porous Pd nanocages with Bi doping: High-performance non-Pt electrocatalysts for ethanol oxidation reaction

Modifying the electronic structure and optimizing the geometric structure can expeditiously tune the electrocatalytic properties of catalysts, resulting in considerably enhanced electrocatalytic performance towards electrocatalytic oxidation of liquid fuels. We herein report a simple synthetic strategy to prepare Bi-doped 3D taraxacum-like Pd nanocages (NCs) composed of porous nanosheets, which possess high surface areas and strong synergistic effects. Notably, a trace of Bi diffuses into the lattice of Pd and increases the electronic effects of the surface of Pd, endowing PdBi-0.5 NCs/C with superior electrocatalytic performance towards ethanol oxidation reaction (EOR). The mass activity and specific activity of PdBi-0.5 NCs/C were 3494.8 mA mgPd−1 and 10.37 mA cm−2, being 4.08- and 4.82- fold enhancements as compared with commercial Pd/C, respectively. Moreover, the highly open porous 3D nanocages structure with rich active sites and defects can also facilitate the mass/electron transfer to favor the EOR kinetics.

Design of Multiservice Code (MS) in Spectral/Temporal/Spatial Domain for OCDMA System

AbstractThis paper explores the design of multiservice code (MS) in spectral, time spreading and wavelength domains (3-Dimensional). The proposed 3D code is designed in such a manner that follows the ideal in phase unit cross correlation in spectral, time spreading and wavelength domains. The proposed encoder generates the MS code effectively in 3D domain and decoder suppresses the multi-user interferences successfully. Performance analyses are carried out by considering the all noises such as phase induce intensity noise(PIIN), shot noise and thermal noise. The analysis of 3D-MS code for variable code length is also performed for measurement of variation in bit error rate against the received power and number of active users in the design. The observed performances are also compared with existing codes such as 2D-MDW, 3D-PDC and 1D-MS code and the proposed code shows the better performance. The analysis of bit error rate of proposed code is carried out against the number of users at 0.622Gbits/s data rate and 0 dBm received power and comparison is also formed with the existing code such as 3D PD(M=21, N=3, P=3), 2DMDW(M=63, P=3), PDC(M=57, P=3) and 1D MS Code. It is noted that 3D MS code shows the better performance than the existing methods. Analysis is also evaluated for variable weight and variable length codes in order to observe the variation in bit error rate with variation in received power and number of simultaneous users.

In Situ Engineering of Pd Nanosponge Armored with Graphene Dots Using Br- toward High-Performance and Stable Electrocatalyst for the Hydrogen Evolution Reaction.

In this study, we report a facile synthetic pathway to three-dimensional (3D) Pd nanosponge-shaped networks wrapped by graphene dots (Pd@G-NSs), which show superior electrocatalytic activity toward the hydrogen evolution reaction (HER) and exhibited excellent long-term stability in acidic media. Pd@G-NSs were synthesized by simply mixing Pd precursors, reducing agent, carbon dots (Cdots), and Br- ion at 30 °C. Experimental results and density functional theory (DFT) calculations suggested that the Br- ions played an essential role in accelerating the exfoliation of Cdot, supplying graphene layers, which could wrap the nanosponge-shaped Pd and finally form Pd@G-NS. In the absence of the Br- ions, only aggregated Pd nanoparticles (NPs) were formed and randomly mixed with Cdots. The resultant Pd@G-NS exhibited a high electrochemically active surface area and accelerated charge transport characteristics, leading to its superior electrocatalytic activity toward the HER in acidic media. The HER overpotential of Pd@G-NS was 32 mV at 10 mA cm-2, and the Tafel slope was 33 mV dec-1. Furthermore, the unique Pd@G-NS catalyst showed long-term stability for over 3000 cycles in acidic media as well, owing to the protection of Pd nanosponges by graphene dot wrapping. The overall HER performance of the Pd@G-NS catalyst exceeded that of commercial Pt/C.

Life-Cycle Assessment of Gingko-Wood Three-Dimensional Membrane for Wastewater Treatment.

Forest is one of nature’s most generous gifts to human beings, providing materials and shelters for all living beings with over 30% global land coverage. Apart from being sustainable, biodegradable, and renewable, wood is also extremely fascinating from the application aspect, with numerous advantages including hierarchical and macroporous structure, excellent mechanical performance, and versatile chemistry. The macroporous structure of wood is comprised of numerous long, partially aligned channels along the growth direction. This structure is suitable for a range of emerging applications, especially as a separation/membrane material. In this research, the potentiality of Gingko biloba (Gb) wood in the remediation of wastewater, contaminated with methylene blue (MB), a dye found in the industrial waters, was investigated. We report a macroporous, three-dimensional (3D) Gb-wood membrane decorated with palladium nanoparticles (Pd NPs) for efficient wastewater treatment. The efficiency of the Pd NPs/Gb-wood membrane to remove MB from a flowing aqueous solution was demonstrated. The wastewater treatment rate of the 3D Pd NPs/Gb-wood membrane can reach 0.5 L/min, with a high MB removal efficiency (>99.9%). The 3D Gb-wood macroporous membrane with partially aligned channels exhibits promising results for water treatment and is applicable for an even wider range of separation applications. In addition, the benefit of this 3D-wood membrane system for wastewater treatment was evaluated against the potential impacts on the environment and human health by employing the life-cycle assessment (LCA) approach. The LCA was carried out using the Gabi-education version with the gate-to-grave approach, including industrial wastewater, 3D-wood membrane, and electricity consumption using CML (Centrum VoorMilieukunde Leiden). From the LCA, it can be observed that wastewater filtration using this membrane exhibited a better environmental footprint due to the improved performance of the membrane in treating a higher volume of the permeate. Therefore, this filtration system had outweighed the additional environmental impact of the wastewater treatment process. The energy demand was identified as the main environmental hotspot in the LCA analysis. The analysis revealed that the energy source for electricity generation had a significant influence on the overall sustainability of this system. Additionally, the wood itself, a naturally abundant and eco-friendly material, presented zero environmental hazard to the environment during the filtration process. The experimental and environmental impact results indicate that Gb-wood can be employed as a natural and eco-friendly adsorbent material for the removal of waste from aqueous solutions.

Non-Rigid Multi-Modal 3D Medical Image Registration Based on Foveated Modality Independent Neighborhood Descriptor.

The non-rigid multi-modal three-dimensional (3D) medical image registration is highly challenging due to the difficulty in the construction of similarity measure and the solution of non-rigid transformation parameters. A novel structural representation based registration method is proposed to address these problems. Firstly, an improved modality independent neighborhood descriptor (MIND) that is based on the foveated nonlocal self-similarity is designed for the effective structural representations of 3D medical images to transform multi-modal image registration into mono-modal one. The sum of absolute differences between structural representations is computed as the similarity measure. Subsequently, the foveated MIND based spatial constraint is introduced into the Markov random field (MRF) optimization to reduce the number of transformation parameters and restrict the calculation of the energy function in the image region involving non-rigid deformation. Finally, the accurate and efficient 3D medical image registration is realized by minimizing the similarity measure based MRF energy function. Extensive experiments on 3D positron emission tomography (PET), computed tomography (CT), T1, T2, and (proton density) PD weighted magnetic resonance (MR) images with synthetic deformation demonstrate that the proposed method has higher computational efficiency and registration accuracy in terms of target registration error (TRE) than the registration methods that are based on the hybrid L-BFGS-B and cat swarm optimization (HLCSO), the sum of squared differences on entropy images, the MIND, and the self-similarity context (SSC) descriptor, except that it provides slightly bigger TRE than the HLCSO for CT-PET image registration. Experiments on real MR and ultrasound images with unknown deformation have also be done to demonstrate the practicality and superiority of the proposed method.

Stable, regenerable and 3D macroporous Pd (II)-imprinted membranes for efficient treatment of electroplating wastewater

Pd (II) from release-unbridled electroplating wastewater is causing great challenges, which is unfavourable either to human health or resource reutilization. Ion-imprinted membranes (IIMs) have recently drawn attentions for selective separation of specific ions from analogues. In this context, we have developed a facile strategy for fabrication of Pd (II)-imprinted membranes (Pd-IIMs) for the selective separation of Pd (II). The enhanced flux was obtained by three-dimensional macroporous structure on polydimethylsiloxane (PDMS). Then the Pd-IIMs were synthesized by a modification-imprinting strategy based on PDMS substrates. With the existence of Co (II), Cu (II), Cd (II) and Ni (II), the as-obtained Pd-IIMs showed superior adsorptive selectivity (3.32–5.06) and perm-selectivity (2.34–4.04) towards Pd (II), as well as the satisfactory regeneration performance (more than 92% of the initial rebinding capacities after 5 cycles of adsorption/desorption). Moreover, the as-prepared Pd-IIMs also displayed stability on separation factors even under ultrasonic treatment. Notably, the overused Pd-IIMs after applications for selective separation of Pd (II) showed a satisfactory performance for the treatment of methylene blue (99.87%), which displayed potentials for the “further applications”. The Pd-IIMs and preparationstrategy developed in this work have shown a positive opportunity for the efficient treatment of electroplating wastewater and organic dyes.

“Romanesco broccoli”-like palladium nano-fractals for superior methanol electro-oxidation

Palladium nanoscale particles possessing distinct planes/facets for fuel cell applications are challenging to construct using simple methods. This work exhibits a facile-solution phase room-temperature synthesis of highly branched and exceptionally ordered 3D Pd nano-fractals (200–300 nm). Using high-resolution atomic imaging, we explain the mechanism of growth and proliferation of facets after twinning. Due to its unique and novel shape, there is an unprecedented 2.025 eV blue shift in d-region of XPS spectra of Pd nano-fractals indicating a phenomenal increase in surface electron density. This is highly favorable for utilizing this promising catalyst for enhanced surface activity. The Pd nano-fractal structures are tested as anodic material, and they show significantly enhanced electrocatalytic activity and superior long-term stability towards methanol oxidation reaction in alkaline media. Thus, low-index enclosed Pd nanostructures could be useful catalysis materials if uniquely shaped and morphologically controlled at nanoscales.

Frontispiece: Reversible Aqueous Zinc–CO2 Batteries Based on CO2–HCOOH Interconversion

Zinc–CO2 Batteries. A reversible aqueous Zn–CO2 battery is prepared by Y. Wang et al. in their Communication on page 16996 ff. 3D porous Pd interconnected nanosheets act as the cathode and electrocatalyze CO2 reduction and HCOOH oxidation.

Reversible Aqueous Zinc-CO2 Batteries Based on CO2 -HCOOH Interconversion.

As a promising technique for CO2 fixation/utilization and energy conversion/storage, the metal-CO2 battery has been studied to improve its interconversion between CO2 and carbonates/oxalates. Herein, we propose and realize a reversible aqueous Zn-CO2 battery based on the reversible conversion between CO2 and liquid HCOOH on a bifunctional Pd cathode. The 3D porous Pd interconnected nanosheet with enriched edge and pore structure, has a highly electrochemical active surface to facilitate simultaneous selective CO2 reduction and HCOOH oxidation at low overpotentials. The resulting battery has a 1 V charge voltage, a cycling durability over 100 cycles, and a high energy efficiency of 81.2 %. The battery mechanism is proposed as Zn+CO2 +2 H+ +2 OH- ↔ ZnO+HCOOH+H2 O, through which the reversible conversion between CO2 and liquid HCOOH was realized.