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Chemical looping gasification (CLG) technology is an effective approach to converting wood waste into high-quality syngas. In the present work, the reactivity of natural hematite is enhanced by doping with nickel oxide (NiO), and the effects of various operating parameters upon the CLG of wood waste are investigated using the NiO-modified hematite as an oxygen carrier. The NiO-modified hematite gives a significantly increased carbon conversion of 79.74%, and a valid gas yield of 0.69 m3/kg, compared to 68.13% and 0.59 m3/kg, respectively, for the pristine (natural) hematite, and 54.62% and 0.55 m3/kg, respectively, for the Al2O3, thereby indicating that the modification with NiO improves reactivity of natural hematite towards the CLG of wood waste. In addition, a suitable mass ratio of oxygen carrier to wood waste (O/W) is shown to be beneficial for the production of high-quality syngas, with a maximum valid gas yield of 0.69 m3/kg at an O/W ratio of 1. Further, an increase in reaction temperature is shown to promote the conversion of wood waste, giving a maximum conversion of 86.14% at reaction temperature of 900 °C. In addition, the introduction of an appropriate amount of steam improves both the conversion of wood waste and the quality of the syngas, although excessive steam leads to decreases in the reaction temperature and gas residence time. Therefore, the optimum S/B (mass ratio of steam to biomass) is determined to be 0.4, giving a carbon conversion and valid gas yield of 86.63% and 0.94 m3/kg, respectively. Moreover, the reactivity of the NiO-modified hematite is well-maintained during 20 cycles, with a carbon conversion and valid gas yield of around 79% and 0.69 m3/kg, respectively. Additionally, the XRD and SEM-EDS analyses indicate no measurable change in the crystal phase of the re-oxidized oxygen carrier.

A novel ITO/NiO/Cu 2 O structure served as photocathodes was applied in photoelectrochemical (PEC) water splitting for the first time. The NiO integration is found to slightly ameliorate the crystalline structure of Cu 2 O. PEC measurements showed that NiO-modified Cu 2 O photocathodes can deliver a higher PEC performance, as the photocurrent density was up to − 1.68 mA/cm 2 at − 0.6 V versus RHE under simulated AM 1.5G illumination, which is 2.8 times higher than that of nude one. The enhanced PEC performance may come from the improved charge separation and migration properties of NiO modification.

The blooming requirement of high‐performance energy storage systems has aroused the thirst for advanced energy storage materials. As a high capacity anode, however, the application of NiO nanoparticles (NiO NPs) is hindered by intractable issues of dramatic volume change, intrinsic low electronic conductivity, and severe aggregation tendency during lithiation/delithiation. Herein, a polydopamine (PDA) assisted bi‐functionalization strategy for fabricating of PDA@NiO‐CNT composites for fast and durable lithium storage is reported. In this composite, CNTs intertwine to form a network to ensure sufficient electrolyte infiltration and act as a highly conductive system to motivate fast charge transmission. The strong binding affinity of PDA facilitates bonding between NiO NPs and CNTs, which not only forms uniform and flexible PDA coating but also ensures homogeneous distribution of NiO NPs on CNTs network. Therefore, the bi‐functional modified PDA@NiO‐CNT electrode possesses high conductivity, alleviates volume change and aggregation of NiO NPs during cycling, achieves a reversible capacity of 1326 mAh g−1 at 100 mA g−1, a rate capability of 215 mAh g−1 at 2000 mA g−1 and a cycling stability with 78% capacity retention after 250 cycles. This bi‐functional modification approach manifests its prospective potential for architecting other electrode materials toward high‐performance electrochemical devices. Polydopamine‐assisted bi‐functional synthesis of NiO nanoparticles homogeneously anchoring on networking carbon nanotubes (PDA@NiO‐CNTs) is prepared to provide high electronic conductivity and prevent particles aggregation, also alleviate the volume expansion of NiO during cycling. These attractive advantages endow the PDA@NiO‐CNTs anode with high reversible capacity, excellent cycling stability, and long durable life in lithium−ion batteries.

In this study, we positioned three quaternary ammonium halide-containing cellulose derivatives (PQF, PQCl, PQBr) as interfacial modification layers between the nickel oxide (NiOx) and methylammonium lead iodide (MAPbI3) layers of inverted perovskite solar cells (PVSCs). Inserting PQCl between the NiOx and MAPbI3 layers improved the interfacial contact, promoted the crystal growth, and passivated the interface and crystal defects, thereby resulting in MAPbI3 layers having larger crystal grains, better crystal quality, and lower surface roughness. Accordingly, the photovoltaic (PV) properties of PVSCs fabricated with PQCl-modified NiOx layers were improved when compared with those of the pristine sample. Furthermore, the PV properties of the PQCl-based PVSCs were much better than those of their PQF- and PQBr-based counterparts. A PVSC fabricated with PQCl-modified NiOx (fluorine-doped tin oxide/NiOx/PQCl-0.05/MAPbI3/PC61BM/bathocuproine/Ag) exhibited the best PV performance, with a photoconversion efficiency (PCE) of 14.40%, an open-circuit voltage of 1.06 V, a short-circuit current density of 18.35 mA/cm3, and a fill factor of 74.0%. Moreover, the PV parameters of the PVSC incorporating the PQCl-modified NiOx were further enhanced when blending MAPbI3 with PQCl. We obtained a PCE of 16.53% for this MAPbI3:PQCl-based PVSC. This PQCl-based PVSC retained 80% of its initial PCE after 900 h of storage under ambient conditions (30 °C; 60% relative humidity).

Charge carrier separation is considered as a key factor in enhancing the photocatalytic process and can be maximized by mitigating surface recombination. Following this idea, the surface of zinc oxide (ZnO) was modified by thermal treatment and nickel oxide (NiO) deposition. The influence of the ZnO thermal treatment and NiO deposition conditions on the ZnO surface chemistry and heterostructure interface properties were investigated by in situ X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) and correlated to the dye photodegradation efficiency. The XPS analysis confirmed a change of doping of ZnO after thermal treatment, which mainly influenced the developed band bending, and has led to an improved photocatalytic activity. For the same reason, the heterostructures based on the surface cleaned ZnO surface had higher photocatalytic efficiency than the ones based on non-cleaned ZnO. The temperature input during NiO deposition had negligible effect on the heterostructure interface properties. The photocatalytic efficiency did not follow the band bending evolution because of a dominant contribution of charge recombination across the NiO layer as indicated by PL analysis. Graphical Abstract

Evolutions on structural, morphological, optical and electrical characteristics of Pt/p-NiO/n-Si/Al thin-film heterojunction diodes before and after various thermal annealing temperatures have been investigated in details. Increases in the annealing temperature improve the crystalline structures of the films, i.e., stress on the film decreases and grain size of the film increases after annealing. The surface roughness of the films enhances from 3.60 to 4.59 nm, especially after 600 °C annealing. This rise in the surface roughness is possible due to the increase in the grain size of the films which causes swelling effect after high-temperature annealing. The energy band gap of the NiO films changes from 3.43 eV to 3.34 eV after annealing temperature up to 450 °C, while it slightly increases after 600 °C annealing process. These observed variations on the band gap values are due to the changes on the crystalline, microstructure and interfacial parameters of the films. On the other hand, the surface modifications also affect the electrical characteristics of the heterojunction diodes. The lowest sheet resistance is obtained to be 65.2 Ω/sq after 450 °C annealing process. Reverse saturation current increases up to 34.1 nA and barrier height also decreases from 0.82 eV to 0.75 eV depending on the annealing temperature. In addition, the lowest value of the ideality factor is obtained to be 1.51 for the diodes annealed at 450 °C. It can be concluded that the annealing-induced surface modifications significantly affect the electrical performance of the diodes and the optimum annealing temperature is 450 °C for the heterojunction diode applications of the p-NiO/n-Si films.

As a famous hole transporting material, nickle oxide (NiO x ) has drawn enormous attention due to its low cost and superior stability. However, the relatively low conductivity and high-density surface trap states of NiO x severely limit device performance in solar cell applications. Interfacial engineering is an efficient approach to achieve remarkable hole-transporting performance by surface passivation. Herein, the efficient NiO x hole transport layer was prepared by surface passivation engineering strategy via facile solution processes with cesium iodide (CsI). It is demonstrated that CsI plays a super-effective dual-function role in inverted solar cell device: On one hand, the presence of CsI hugely passivates the surface trap states at the NiO x /perovskite interface along with obviously improved conductivity by the incorporated Cs + ; on the other hand, the ions immigration is significantly suppressed by the presence of I ion for high-quality perovskite films, resulting in a stable contact interface. The ameliorative interface leads to largely reduced carrier non-radiative recombination, attributing to boosted carrier extraction efficiency. As a result, decent power conversion efficiency (PCE) of 18.48% with a noticeable fill factor (FF) beyond 80% was achieved. This facile and efficient surface engineering approach with dual-function shows excellent potential for the design of high-performance functional interfacial modification layer to achieve high-performance solar cells.

Currently, embedded systems can be found everywhere in quotidian life. In the development of embedded systems, information security is one of the important factors. Encryption is an efficient technique to protect information against attacks. However, because of constraints, existing encryption functions are not compatible and do not agree with real-time applications in embedded systems. In this paper, an improved cryptographic approach with a high level of security and high speed is put forward. Our work uses an efficient version of a hybrid scheme comprising an Advanced Encryption Standard (AES) - Elliptic Curve Cryptography (ECC) for medical image encryption, which combines the benefits of the symmetric AES to speed-up data encryption and asymmetric ECC in order to secure the interchange of a symmetric session key. The contribution of this paper consists of the following two main points: First, we put forward an optimized ECC hardware architecture to respect the compromise between area, power dissipation, and speed. Thus, we primarily utilize only two multipliers to develop the Point Addition (PA) block and the Point Doubling (PD) block, which reduces time complexity. Then, a 32-bit multiplier and a 32-bit inverter architecture based on shifts and XORs are proposed to reduce power consumption and area occupancy. Second, for image encryption, we primarily propose to modify the AES by eliminating the mix-columns transformation and replacing it with a permutation based on the shifts of columns, which decreases time complexity while maintaining the Shannon diffusion and the confusion principle. Then, an adjustment of the rearrangement of the general structure is given to enhance the entropy value. The global cryptosystem is implemented using a co-design approach where the modified AES runs on the NIOS II processor, and the scalar ECC multiplication is designed as a hardware accelerator. The suggested cryptographic system spends much less execution time, which is a significant factor for being applied in practice. Security analysis is successfully performed, and our experiments prove that our proposed technique provides the basics of cryptography with more simplicity and correctness. In fact, the results of the evaluation prove the effectiveness, rapidity and high security of the suggested algorithm.

Ferulic acid is a natural phenolic antioxidant with anticancer medicinal properties. A new electrochemical strategy based on the twofold modification of carbon paste electrode with NiO-embedded single-wall carbon nanotube nanocomposite and n-methyl-3-butylimidazolium bromide (CPE/MBIBr/NiO-SWCNTs) is suggested for the first time and the fabricated sensor is recommended as a voltammetric tool for the determination of ferulic acid in the presence of butylated hydroxytoluene (BHT). The CPE/MBIBr/NiO-SWCNTs are employed toward the study of the electro-oxidation behavior of ferulic acid in aqueous buffer solution in the pH range of 3.0–6.0. The CPE/MBIBr/NiO-SWCNTs exhibit a potent electron mediating toward the ferulic acid electro-oxidation and also extravagantly resolve the oxidation signals of ferulic acid and BHT for the simultaneous analysis of these food additives. The limit of detection for ferulic acid and BHT are found to be 20.0 nM and 0.1 µM, respectively. The CPE/MBIBr/NiO-SWCNTs are applied for the direct analysis of ferulic acid and BHT in corn milk, wheat flour, and corn cider samples.

A series of mesoporous NiO catalysts with high specific surface area were prepared by a simple hydrothermal method and modified by cetyltrimethylammonium bromide (CTAB) as the crystal structure directing regent. The characterization with SEM, XRD, BET, and H2-TPR results demonstrated that the introduction of CTAB effectively improved the dispersion, specific surface area, and pore volume and redox ability of NiO, and thus exposed more active sites. Meanwhile, the NiO catalyst with a CTAB/NiSO4·6H2O molar ratio of 2/3 exhibited the better catalytic ozonation performance of toluene, formaldehyde, methanol, and ethyl acetate than NiO. The in-situ DRIFTS elucidated the reaction path of catalytic ozonation of toluene and indicated that the introduction of CTAB facilitated the complete oxidation of by-products into CO2 and H2O.