Hollow NiO Research Articles

Preparation and Electrochemical Investigation of NiO Hollow Sphere from Bio Waste (Sugarcane Bagasse) Extract for Energy Storage Applications

Preparation and Electrochemical Investigation of NiO Hollow Sphere from Bio Waste (Sugarcane Bagasse) Extract for Energy Storage Applications

Carbon-doped nickel oxide hollow nanospheres for enhanced photocatalytic CO2 reduction

Through artificial photosynthesis the conversion of CO2 assisted by photocatalyst is conducive to alleviating greenhouse effect and energy shortage. Herein, the carbon-doped NiO hollow nanospheres (C-NiO) were constructed by using the glucose-based carbon spheres as sacrificial template and dopants of carbon. The obtained C-NiO samples with adjustable carbon content show high specific surface area (114.02–139.49 m2·g−1) as compared with NiO (13.93 m2·g−1), which is beneficial to the adsorption and activation of more CO2 molecules, thereby improving CO2 photo-reduction. As expected, the C-NiO samples convert CO2 into CO and CH4 with high yield efficiency and stability due to the hollow nanostructure and the carbon-doping, which could increase CO2 adsorption and light utilization, gain more active sites, reduce band gap and propel the charge separation and migration. The optimization of morphology and composition of photocatalysts is an effective strategy for the enhancement of CO2 photo-reduction, suggesting the great application prospect of the carbon-doped NiO hollow nanospheres in photocatalysis.

Co Ion‐, NiS2‐ and CNT‐Co‐Doped Nanoflower/Hollow Spherical NiO Nanocomposites for Efficient Electrocatalytic Oxidation of Methanol

AbstractNowadays, the development and utilization of clean energy are becoming increasingly urgent. Among them, methanol is a new, clean, and efficient energy source. Therefore, more and more studies are focusing on methanol anodic oxidation (MOR). In this work, nanoflower and hollow spherical NiO was synthesized by a simply hydrothermal method and then modified by Co ion, NiS2 and carbon nanotubes (CNTs). The optimal Co/NiO(f)/NiS2−CNT exhibits flower‐like morphology with a larger specific surface area, enlarged electrochemically active surface area and higher conductivity, which improve the electron transfer ability and electrocatalytic activity compared with pure NiO(f), NiO(f)/NiS2, NiO(f)/NiS2−CNT and hollow spherical Co/NiO(hs)/NiS2−CNT. The current density is ultrahigh of 203.46 mA ⋅ cm−2 at 0.8 V, which is 36 times higher than pure NiO(f) and almost 2 times higher than Co/NiO(hs)/NiS2−CNT. Therefore, this work offers a highly efficient and stable NiO based catalyst for methanol oxidation reaction.

C12-2-C12mim][Br2]-assisted hydrothermal synthesis of hollow NiO microspheres for near-room temperature measurement of H2S

Hollow NiO microspheres were prepared using one-step hydrothermal method assisted by geminal dicationic ionic liquid (DIL) 1, 2-bis (N-dodecylimidazolyl) ethane bromide ([C12-2-C12mim][Br2]). The structures of the prepared microspheres can be controlled by adjusting the concentration of ionic liquid and reaction temperature. Furthermore, the amount of ionic liquid residue in these microspheres can also be controlled by changing the calcination temperature. Among them, the NiO hollow microspheres prepared by calcining the precursor at 600 °C (Ni1–600) in air display the most excellent gas sensing performance, including high response (35.6–100 ppm H2S) and low working temperature (50 °C). The excellent gas sensing performance of the Ni1–600 is attributed to the ionic liquid residue with appropriate content, which enhances the interaction between the analyte and the sensing material. The strong interaction effectively increases the sensitivity and reduces the working temperature of the sensor. The NiO hollow microspheres are expected to be a promising candidate material for the highly sensitive H2S gas sensor at near room temperature.

Dual Atoms (Fe, F) Co-Doping Inducing Electronic Structure Modulation of NiO Hollow Flower-Spheres for Enhanced Oxygen Evolution/Sulfion Oxidation Reaction Performance.

Heteroatoms Fe, F co-doped NiO hollow spheres (Fe, F-NiO) are designed, which simultaneously integrate promoted thermodynamics by electronic structure modulation with boosted reaction kinetics by nano-architectonics. Benefiting from the electronic structure co-regulation of Ni sites by introducing Fe and F atoms in NiO , as the rate-determined step (RDS), the Gibbs free energy of OH* intermediates (ΔGOH* ) for Fe, F-NiO catalyst is significantly decreased to 1.87eV for oxygen evolution reaction (OER) compared with pristine NiO (2.23eV), which reduces the energy barrier and improves the reaction activity. Besides, densities of states (DOS) result verifies the bandgap of Fe, F-NiO(100) is significantly decreased compared with pristine NiO(100), which is beneficial to promote electrons transfer efficiency in electrochemical system. Profiting by the synergistic effect, the Fe, F-NiO hollow spheres only require the overpotential of 215mV for OER at 10mA cm-2 and extraordinary durability under alkaline condition. The assembled Fe, F-NiO||Fe-Ni2 P system only needs 1.51V to reach 10mA cm-2 , also exhibits outstanding electrocatalytic durability for continuous operation. More importantly, replacing the sluggish OER by advanced sulfion oxidation reaction (SOR) not only can realize the energy saving H2 production and toxic substances degradation, but also bring additional economic benefits.

NiO hollow dodecahedrons modified separator regulates the performance of lithium–sulfur battery

Lithium–sulfur battery is a promising energy storage system due to the high theoretical energy density. However, the serious shuttle effect of polysulfides and slow dynamics hinder its further development. Herein, NiO-modified separator was used to solve above problems. Hollow nanostructure alleviates the polysulfides diffusion in both physical and chemical sense. Meanwhile, the abundant mesoporous provide lots of active sites for polysulfides, which effectively catalyzes the electrochemical reaction. Therefore, the modified separator improves the cycle stability and rate performance.

Hollow multi-shelled NiO nanoreactor for nanoconfined catalytic degradation of organic pollutants via peroxydisulfate activation

Nonradical activation of peroxydisulfate (PDS) is promising for wastewater decontamination but suffers from insufficient decomposition efficiency toward organics. Herein, NiO nanospheres with hollow multi-shelled structure (HoMS) and tunable shell numbers are designed as a nanoreactor of PDS activation to enhance the decomposition efficiency. Study on bis-phenol A (BPA) degradation reveals that 3-shelled NiO HoMS exhibits enhanced kinetic rate (0.08 min1) and mineralization degree (79.2%) compared to 2-shelled NiO HoMS (0.04 min−1, 50%) and NiO nanoparticles (0.01 min−1, 29.8%). The degradation of BPA over NiO HoMS follows electron transfer regime with oxygen vacancy (VO) acted as the active site. The hollow multi-shelled structure not only increases the accessibility of VO but also enriches local concentration of reactants in the void spaces due to the nanoconfinement effect, and thus mainly contributes to the enhanced catalytic efficiency. This work provides a distinct case for developing efficient nonradical oxidation technique for water purification.

Hollow nanostructured NiO particles as an efficient electrode material for lithium-ion energy storage properties.

This work has developed a straightforward approach to obtaining NiO hollow structures by using Li2O2 as an easily removable template. The easy availability and electrochemically active nature of NiO have attracted researchers' attention as an anode electrode for Li-ion storage applications, including Li-ion secondary batteries (LIBs) and for Li-ion hybrid supercapacitors (LiHSCs; which offer higher power densities than LIBs without compromising energy density). However, NiO usage has been limited to its low reaction reversibility, poor conductivity, and conversion reaction capability. Recently, hollow nanostructured materials have attracted attention as efficient battery materials due to their fascinating structural features. This study presents a modified Li2O2-assisted method to obtain porous open 3D architectures of NiO nanostructures. The resultant hollow structures are electrochemically studied as an anode for a LIB, exhibiting excellent stability over hundreds of cycles. The result is recognized as one of the finest among NiO anodes reported. Also, NiO hollow structures studied as anodes for LiHSC devices fabricated with activated carbon cathodes exhibit an outstanding comprehensive electrochemical performance which is better than the typical LIB and supercapacitors.

Morphology-modulated rambutan-like hollow NiO catalyst for plasma-coupled benzene removal: Enriched O species and synergistic effects

While catalyst morphology plays an essential role in traditional thermal catalysis, the specific effects in plasma catalysis deserve further in-depth study. In the present study, hollow NiO nanospheres with a rambutan-like structure were successfully prepared by MOFs-derived method involving morphology modulation, and employed for the in-plasma catalytic oxidation of benzene. The results show an enhancement of 60 % for benzene removal, while CO2 selectivity was increased by 20 %. The energy consumption for 95 % benzene removal efficiency (RE95%) was also reduced from 3600 J/L to 1100 J/L. Specifically, the hollow spherical shell structure is more abundant in surface oxygen species, including chemisorbed oxygen and surface lattice oxygen, which can be activated by plasma; the hollow structure also modulates the plasma discharge by shielding effect. The plasma field in turn also excites the oxidation activity of NiO, thus achieving the synergistic effect. In addition, a more comprehensive benzene decomposition pathway is proposed by analysis of the gaseous and non-gaseous intermediates (tar), where the plasma non-selectively breaks the chemical bonds of reactants and the catalyst selectively oxidizes the organic intermediates to CO2, and they promote each other to achieve synergistic effects.

Prussian-blue-analog derived hollow Co3O4/NiO decorated CeO2 nanoparticles for boosting oxygen evolution reaction

Exploration of efficient, inexpensive, and stable electrocatalysts for oxygen evolution reaction (OER) is of great significance for energy conversion and storage. Currently, transition metal oxides (TMOs) show huge potential as electrode materials for OER due to their low-cost, rich redox chemistry and high chemical stability. In this work, we report a facile route for uniformly coating CeO 2 nanoparticles (NPs) on the surface of nickel cobalt Prussian blue analogue (NiCo-PBA) derived Co 3 O 4 /NiO hollow porous nanocubes (Co 3 O 4 /NiO HPN). The accurate control of CeO 2 content on the Co 3 O 4 / NiO HPN (Co 3 O 4 /NiO@CeO 2 HPN) surface can effectively alter the surface electronic states, which tunes the ratio of Co 2+ /Co 3+ and Ni 2+ /Ni 3+ for creating abundant oxygen vacancies. The large surface area of hollow nanocubes derived from NiCo-PBA with porous structure offers more active sites, resulting in the great promotion of OER activity. The prepared Co 3 O 4 /NiO@CeO 2 -2 HPN heterostructure exhibits remarkable OER performance with a low overpotential (290 mV at 10 mA·cm −2 ), small Tafel slope (66 mV dec −1 ) and excellent durability. The present method opens a new avenue to the preparation of low-cost and efficient electrocatalysts in OER. A novel hollow and porous heterostructure of CeO 2 nanoparticles (NPs)-decorated NiO/Co 3 O 4 hollow porous nanocubes (Co 3 O 4 /NiO@CeO 2 HPN) was designed for boosting the oxygen evolution reaction activity. • Co 3 O 4 /NiO@CeO 2 HPN electrocatalyst is designed by an easy to realize strategy. • The microstructure and surface state of the catalyst can be regulated accurately. • Active sites and oxygen vacancies are obtained for boosting the OER performance. • Integration of high catalytic activity and excellent durability together.

Automobile Cab Air Detection Based on Hollow Sphere NiO Gas Sensor

A novel NiO hollow sphere was synthesized by a simple water bath method while the carbon balls served as templates. Characterization and gas-sensing performance of NiO hollow spheres were tested. Owing to its hollow structure, the NiO obtained large specific surface area and abundant active sites. Furthermore, the gas sensors showed the enhanced formaldehyde sensing performance obtained a gas response of 21 to 50 ppm formaldehyde at 300 °C, short response/recovery time as 12 and 20 s, and excellent stability. These results indicate that the NiO hollow spheres play an important role on the VOCs sensing performance for practical detectors.

Camphene-derived hollow and porous nanofibers decorated with hollow NiO nanospheres and graphitic carbon as anodes for efficient lithium-ion storage

A synthesis strategy for hollow and porous nanofibers comprising hollow NiO (H-NiO) nanospheres formed via nanoscale Kirkendall diffusion and supported over a porous graphitic carbon matrix (H-NiO@HNFs) is reported herein to enable the fabrication of advanced anodes for stable lithium-ion batteries (LIBs). The H-NiO@HNFs comprising 1D longitudinal hollow channels ensured efficient diffusion of charged species via effective electrolyte percolation besides providing sufficient space to accommodate the large volume variations during repeated cycling. The hollow NiO nanospheres acted as chemical sites for lithiation and delithiation. Additionally, the H-NiO@HNFs exhibited improved lithium-ion storage properties, such as reasonable rate capability, stable prolonged cyclability at a high current density (1.0 A g-1), and a high lithium-ion diffusion coefficient, primarily owing to their enhanced structural integrity compared to that of filled NiO nanofibers (F-NiO NFs). This facile synthesis approach could broaden the current understanding of 1D hollow nanostructures decorated with conventional hollow metal-oxide nanoparticles for various applications.

A new strategy for efficient light management in inverted perovskite solar cell

The light management is of vital importance for development of efficient inverted perovskite solar cells (PSCs), which could maximize the light trapping and minimize optical loss. Herein, a novelly-designed, functional spherical NiO hole transporting layer (HTL) is reported for the first time to effectively increase light utilization and the final photocurrent of inverted MAPbI3 PSCs. Experimental and theoretical results indicate that such hollow NiO HTLs improves optical field distribution and light harvesting efficiency. This contributes to realize the better light utilization and higher photocurrent of over 24 mA cm−2, which is one of the highest reported values for NiO-based MAPbI3 PSCs. Besides, the synergistic Cu doping strategy was further employed to ensure the enhanced hole extraction and suppressed recombination loss. Eventually, this hollow Cu:NiOx PSCs feature desirable efficiency over 20%, along with the improved open-circuit voltage and low hysteresis. This work demonstrates the necessity of light management and unveils a simple approach for achieving efficient inverted NiO-based devices.

Boosting the energy density of supercapacitors by designing both hollow NiO nanoparticles/nitrogen-doped carbon cathode and nitrogen-doped carbon anode from the same precursor

• The hollow NiO/NC was designed based on the Kirkendall effect. • 2. The pure NC with hollow structure was prepared using the same precursor. • 3. DFT calculations prove that NiO/NC and NC have excellent electrochemical performance. • 4. High-energy–density asymmetric supercapacitor of 40.2 Wh kg −1 was achieved. Designing the transition metal oxide-based electrode with hollow nanostructure is of great importance for high-performance supercapacitors. Here, the hollow NiO encapsulated in a nitrogen-doped carbon matrix (NiO/NC) is synthesized by using the precursor of Ni-based metal–organic complex based on the Kirkendall effect. With the same precursor, the hollow NC is obtained by removing the Ni element through an acid etching method. Density functional theory (DFT) calculations convince that both hollow NiO/NC and NC have high electrical conductivity and adsorption energy for OH – , demonstrating their high practicability for supercapacitor applications. In a three-electrode system, the NiO/NC sample prepared under 700 °C displays a high specific capacitance (1026 F g −1 at 1 A g −1 ) and excellent cycle stability (80.2% capacity retention over 8000 cycles). Importantly, a high energy density of 40.2 Wh kg −1 was achieved based on the asymmetric supercapacitor assembled with NiO/NC cathode and NC anode. This work provides new insights on designing high-performance electrode materials to boost supercapacitor performance using the same precursor.

Electrospun 1D-NiO hollow nanowires on glass support for the sunlight-driven photodegradation of methylene blue.

Sunlight-driven semiconductor photocatalysts have received substantial attention due to environmental degradation, but a simple and reusable photocatalyst design has been a challenging task. Herein, we report the fabrication of a one-dimensional hollow semiconducting nanowire structure by electrospun-mediated nickel oxide nanowires (NiO NWs) as a reusable photocatalyst by direct deposition on glass substrates. The effective control of the sunlight-driven hollow nanowires as the photocatalyst has a high surface area for multiple light-harvesting and interface redox reactions, a nanostructured thin shell for accelerated charge separation, transportation, and a large length-diameter ratio for easy recycling. The electrospun NiO NWs were nest-like hollow nanostructure fibers, crystalline, and with a high density, and the synthesis and parameters were thoroughly investigated to achieve the characteristic shape of the hollow NiO NWs. Further, the photocatalytic activity of the NiO NWs on glass substrates for the selective breakdown of methylene blue (MB) under sunlight irradiation to optimize the efficiency of the NiO NWs, such as degradation techniques, concentration, and pH of the MB solution. The stability and reusability of the NiO NWs were tested successfully in several reusable cycles, with only a 2% degradation difference. The reaction rate was found to be 0.054 min-1 for MB (5 μM) and 0.033 min-1 for MB (10 μM) at pH 11 for 60 min, and the higher activity parameter was calculated to be 3.3 × 10-3 min-1 mg-1 L-1 due to their hollow structure and effective area of the NiO NWs. They contain more superficially-entrapped holes that change with chemisorbed oxyhydroxyl OH or H2O to form OH- radicals. The specific active hollow surface area rises, whereas the rate of optical-electronic hole recombination drops. The photocatalytic degradation performance of the fabricated one-step electrospun hollow NiO NW-based photocatalyst on substrates showed speed, reusability, and promoted the formation of radicals capable of decomposing organic pollutants, which were shown to have application in photocatalysis.

Self-templating hydrothermal synthesis of carbon-confined double-shelled Ni/NiO hollow microspheres for diphenylamine detection in fruit samples

Toxic substances, such as heavy metals, toxins, pesticides, pathogens, and veterinary drug residues in food are hazardous to consumer health. The variety and quantity of food consumption have increased owing to developments in the agricultural and food industries. Food safety has a substantial socioeconomic impact, and an increasing number of consumers have become aware of its importance. Therefore, simple and cost-effective analytical methods are required to quantify the safety of preservatives. Herein, we report an electrochemical method using double-shelled carbon-confined Ni/NiO (C@Ni/NiO) hollow microspheres to detect diphenylamine (DPA). The microspheres were synthesized by a self-templating hydrothermal method followed by calcination. The hydrothermal temperature and precursor ratio were optimized systematically to prepare double-shelled C@Ni/NiO hollow microspheres. The excellent electrocatalytic activity and electron transport properties of a C@Ni/NiO-modified glassy carbon electrode (GCE) were exploited in the electrochemical oxidation of DPA. Interestingly, the engineered C@Ni/NiO/GCE has a wide dynamic linear range (0.02–473 μM) and a DPA detection limit of 0.007 μM. In addition, the DPA sensor exhibited good selectivity, reproducibility, repeatability, and stability. The practical feasibility of the DPA sensor was evaluated in fruit samples (sweet tomatoes, apples, and red grapes), with considerable recovery.

Design and preparation of hollow NiO sphere- polyaniline composite for NH3 gas sensing at room temperature

The accurate and rapid sensing of NH3 at room temperature is a challenging conundrum for daily life and environment protection. In this work, we have explored an intriguing material, hollow NiO sphere composited with polyaniline (labelled as h-NiO-PANI) for NH3 gas sensing, fabricated by growing PANI on the hollow NiO sphere derived from solvothermal synthesis and calcination. Ni-Cu glycerate is obtained via solvothermal synthesis, which is a universal way to produce uniform glycerate microspheres. During calcination, the hollow sphere is ingeniously designed by taking advantage of the outward adhesion from CuO to the inner core. Polymerization of aniline on the hollow spheres is beneficial for large specific surface area and gas adsorption. Impressively, the sensor based on h-NiO-PANI exhibits favorable response to NH3 (ΔR/R0=43 % for 10 ppm, 149 s in response and 257 s in recovery), which is greatly better than the counterparts (NiO-PANI and PANI). Moreover, the sensor has also shown superb anti-interference against common volatile organic compounds (VOCs), water and humidity, along with the superior repeatability in 5 cycles and long-term stability in a week, manifesting the sensor a promising candidate in daily application. The enhanced gas sensing performance is attributed to the hollow structure and construction of p-p heterojunctions between NiO and PANI.

Single layered hollow NiO–NiS catalyst with large specific surface area and highly efficient visible-light-driven carbon dioxide conversion

A sea urchin-shaped, single-layer, and hollow NiO–NiS photocatalyst with a large surface area was designed for carbon dioxide (CO2) conversion in this study. A d-glucose polymeric hollow frame was fabricated using a d-glucose monomer, and NiO particles were stably grown on it using the hydrothermal method to form a hollow NiO surface. The d-glucose frame was removed by heat treatment to create hollowed NiO; hollowed NiO–NiS (h-NiO–NiS) was subsequently obtained through ion exchange between the O ions in NiO and S ions in the sulfur powder. Additionally, we attempted to determine the correlation among the surface area of the h-NiO–NiS catalyst, CO2 gas adsorption capacity, and catalyst performance. The surface area of the h-NiO–NiS catalyst was ten times larger than that of the nanometer-sized NiO–NiS (n-NiO–NiS, 21.2 m2 g−1) catalyst. The CO2 photocatalytic conversion performance of the hollowed catalyst was approximately seven times larger than that of the nanosized catalyst. As the amount of ion-exchanged S increased, methane selectivity increased, and optimal methane production was obtained when the weight ratio of NiO and sulfur powder was 1 : 4. Using temperature-programmed desorption (TPD) analyses of CO2 and H2O, the adsorption of water molecules on the Ni–S surface and that of CO2 gas on the Ni–O surface during CO2 conversion reaction were confirmed. The h-NiO–NiS catalyst facilitated an effective charge separation through a well-developed interfacial transition between the linked NiS and NiO, and resulted in increased CO2 photoreduction performance under sunlight.

Co/La-Doped NiO Hollow Nanocubes Wrapped with Reduced Graphene Oxide for Lithium Storage

Conversion-type NiO material is attractive due to its high theoretical capacity, and yet it displays inadequate reaction sites, a huge volume expansion, and a sluggish ions/electrons’ transport rat...

Triple-shell NiO hollow sphere for p-type dye-sensitized solar cell with superior light harvesting

In this article, new p-DSSC electrodes are fabricated using NiO hollow spheres (HSs) prepared through a facial one-step hydrothermal process. The current-voltage (J-V) curve indicates that p-DSSCs fabricated using triple-shell NiO HS have excellent photoelectrochemical performance, with a photoelectrical efficiency of 1.79%. The UV–vis diffused reflectance spectra indicate that the triple-shell NiO HS, with its unique structure, has superior light reflection, scattering ability and large surface area with more inner cavities, which helps harvest more light. Electrochemical impedance spectroscopy (EIS) further confirms that triple-shell NiO HS shows fast dye regeneration, improved hole transport and suppressed recombination. The research work of unique NiO HS is important for the selection of efficient photocathode materials for p-DSSCs.