NaBH4 Reduction Research Articles

Introducing oxygen vacancies on sodium titanate via NaBH4 treatment for conductometric hydrogen gas sensors

Sodium titanate (NTO) has drawn great attentions in various applications, but few works focus on using NTO as gas sensors. The implication of NTO as gas sensors requires a simple synthesis route to fabricate NTO with large surface areas and oxygen vacancies. Herein, Pd-decorated NTO microscale hierarchical spheres (Pd-NTO MHSs) is synthesized using Ti foil as a precursor·H2O2 is added to promote the preparation of NTO MHSs under a low base-concentration and low temperature condition, making the synthetic route more eco-friendly than previously methods. Additionally, we demonstrate NaBH4 reduction is a one-step process that simultaneously decorates Pd nanoparticles and brings abundant oxygen vacancies on the NTO surface, but too high NaBH4 concentration deteriorates the hydrogen sensing performance. At the optimized condition, Pd-NTO MHSs have a response time of ∼1.8 s to 1% H2 and a wide detection range of 10 ppm to 10% H2 at 25 °C. This study highlights that NaBH4 treatment is an effective strategy for regulating surface chemical properties and introducing oxygen vacancy on NTO, enabling Pd-NTO MHSs an excellent sensing property. It is also helpful for the rational design of NTO as a versatile sensing material with abundant oxygen vacancies to sense other gases.

Ru Single Atoms on One-Dimensional CF@g-C3N4 Hierarchy as Highly Stable Catalysts for Aqueous Levulinic Acid Hydrogenation.

Herein, we report a stable catalyst with Ru single atoms anchored on a one-dimensional carbon fiber@graphitic carbon nitride hierarchy, by assembling wet wipes composed of fiber-derived carbon fiber (CF), melamine-derived graphitic carbon nitride (g-C3N4) and RuCl3 before NaBH4 reduction. The atomically dispersed Ru species (3.0 wt%) are tightly attached via N-coordination provided by exterior g-C3N4 nanosheets, and further stabilized by the interior mesoporous CF. The obtained CF@g-C3N4-Ru SAs catalyst can be cycled six times without notable leaching of Ru or loss of GVL yield in the acidic media. This catalyst is more stable than Ru nanoparticles supported on CF@g-C3N4, as well as Ru single atoms anchored on CF and g-C3N4, and proves to be one of the most efficient metal catalysts for aqueous LA hydrogenation to γ-valerolactone (GVL). The isolated Ru atoms by strong N-coordination, and their enhanced electron/mass transfer afforded by the one-dimensional hierarchy, can be responsible for the excellent durability of CF@g-C3N4-Ru SAs under harsh reaction conditions.

PdPty/V2O5-TiO2: Highly Active Catalysts with Good Moisture- and Sulfur Dioxide-Resistant Performance in Toluene Oxidation

Catalytic performance and moisture and sulfur dioxide resistance are important for a catalyst used for the oxidation of volatile organic compounds (VOCs). Supported noble metals are active for VOC oxidation, but they are easily deactivated by water and sulfur dioxide. Hence, it is highly desired to develop a catalyst with high performance and good moisture and sulfur dioxide resistance in the oxidation of VOCs. In this work, we first adopted the hydrothermal method to synthesize a V2O5-TiO2 composite support, and then employed the polyvinyl alcohol (PVA)-protecting NaBH4 reduction strategy to fabricate xPdPty/V2O5-TiO2 catalysts (x and y are the PdPty loading (0.41, 0.46, and 0.49 wt%) and Pt/Pd molar ratio (2.10, 0.85, and 0.44), respectively; the corresponding catalysts are denoted as 0.46PdPt2.10/V2O5-TiO2, 0.41PdPt0.85/V2O5-TiO2, and 0.49PdPt0.44/V2O5-TiO2). Among all the samples, 0.46PdPt2.10/V2O5-TiO2 exhibited the best catalytic activity for toluene oxidation (T50% = 220 °C and T90% = 245 °C at a space velocity of 40,000 mL/(g h), apparent activation energy (Ea) = 45 kJ/mol), specific reaction rate at 230 °C = 98.6 μmol/(gPt s), and turnover frequency (TOFNoble metal) at 230 °C = 142.2 × 10−3 s−1. The good catalytic performance of 0.46PdPt2.10/V2O5-TiO2 was associated with its well-dispersed PdPt2.10 nanoparticles, high adsorbed oxygen species concentration, good redox ability, large toluene adsorption capacity, and strong interaction between PdPty and V2O5-TiO2. No significant changes in toluene conversion were detected when 5.0 vol% H2O or 50 ppm SO2 was introduced to the reaction system. According to the characterization results, we can realize that vanadium is the main site for SO2 adsorption while PdO is the secondary site for SO2 adsorption, which protects the active Pt site from being poisoned by SO2, thus making the 0.46PdPt2.10/V2O5TiO2 catalyst show good sulfur dioxide resistance.

One-pot synthesis of bimetallic Ni/Ag nanosphere inside colloidal silica cavities for in situ SERS monitoring of the elementary steps of chemoselective nitroarene reduction evidenced by DFTB calculation

Spherically shaped bimetallic Ni/Ag nanocomposite is synthesized in one-pot within colloidal silica cavities in aqueous media in an efficient way and is characterized using UV-Vis, IR, EPR, Raman, powder XRD, SEM, TEM, and SERS. This could trigger the chemoselective NaBH4 reduction of nitoarenes under solvent free conditions at ambient temperature in excellent yields. The process could be scaled up to multi-gram scale without any need for temperature control and organic extractor. This spherical nanocomposite showed good operational stability, robustness and recyclability as is evidenced by a model reaction of 2-nitophenol (2-NP) to 2-aminophenol (2-AP). Reduction of nitroarenes is widely used for the studies of catalytic efficacy of nanoparticles as its mechanism is still unproven in heterogenous condition. Although complicated, a real time monitoring of surface-enhanced Raman scattering (SERS) with discrete steps, by placing the surface-immobilized reactant molecules at the well-defined spherical nanocomposite, we identified dihydroxyazobenzene (DHAB) as the intermediate. The catalysing process was further studied computationally using DFTB level of theory through Nudged elastic band (NEB) method to locate the involved transition states and intermediates. Overall, the results demonstrate that spherical Ni/Ag@silica bimetallic nanocomposite could catalyse the selective activation of NaBH4 reduction of nitoarenes in a fast, clean process and SERS as a powerful tool for studying heterogeneous catalysis and hence, the present catalyst system constitutes one straightforward and environmentally safe approach to a class of much sought organic transformation.

Synthesis of LiDAR-Detectable True Black Core/Shell Nanomaterial and Its Practical Use in LiDAR Applications.

Light detection and ranging (LiDAR) sensors utilize a near-infrared (NIR) laser with a wavelength of 905 nm. However, LiDAR sensors have weakness in detecting black or dark-tone materials with light-absorbing properties. In this study, SiO2/black TiO2 core/shell nanoparticles (SBT CSNs) were designed as LiDAR-detectable black materials. The SBT CSNs, with sizes of 140, 170, and 200 nm, were fabricated by a series of Stöber, TTIP sol-gel, and modified NaBH4 reduction methods. These SBT CSNs are detectable by a LiDAR sensor and, owing to their core/shell structure with intrapores on the shell (ca. 2–6 nm), they can effectively function as both color and NIR-reflective materials. Moreover, the LiDAR-detectable SBT CSNs exhibited high NIR reflectance (28.2 R%) in a monolayer system and true blackness (L* < 20), along with ecofriendliness and hydrophilicity, making them highly suitable for use in autonomous vehicles.

In-situ generation of Bi0 NCs and vacancies on Bi-CTS/BiOBr heterostructures accelerate electron transfer for promoting photocatalytic reduction of CO2

Developing high-efficiency photocatalysts for CO2 conversion remains a challenge. Herein, S-scheme Bi-Cu3SnS4/BiOBr heterojunction with S, O defective vacancies was successfully prepared by hydrothermal process and NaBH4 reduction method. Characterization results showed that the Cu3SnS4 nanoparticles were uniformly dispersed onto the BiOBr nanosheets, with Bi0 nanoclusters (NCs) serving as a bridge between the BiOBr and Cu3SnS4. The S-scheme heterojunction was demonstrated via ultraviolet photoelectron spectrometer (UPS) work function. The surface plasma resonance (SPR) effect of Bi0 NCs, the internal electric field (IEF) and S, O defects coregulation of Fermi level equilibrium enhanced light utilization and facilitated photogenerated carriers’ separation, resulting in superior photocatalytic activity. Under visible light illumination, the Bi-Cu3SnS4/BiOBr(30) achieved CO yield of about 50.13 μmol·g−1·h−1 within 120 min, which was 3.5 times of pristine Cu3SnS4 (15.6 μmol·g−1·h−1). Moreover, it exhibited the highest incident photon-electron conversion efficiency (10.58% at 380 nm). This study could provide a reference for designing efficient S-scheme heterojunctions for photocatalytic reduction of CO2.

Treatment of wastewater from the flocculation process of waste cutting fluid by zerovalent iron catalyst

Waste cutting fluids are considered as hazardous wastes because they contain numerous different components causing environmental problems. Normally, a flocculation method is applied to treat preliminarily. However, the output wastewater still needs treating further to meet the national standards of industrial wastewater before disposal. So, this research reports the secondary treatment stage of the waste cutting fluid collected from an industrial factory in Vietnam using zero valent iron (ZVI) catalyst. This catalyst was synthesized via a redox reaction between sodium borohydride (NaBH4) and ferric chloride (FeCl3). Key factors affecting the quality of the ZVI particles such as the concentration of the NaBH4 reductant, reaction temperature, and dropping rate were investigated systematically. At the optimum synthesis conditions, viz. the NaBH4 concentration of 0.2 M, reaction temperature of 25 oC and the dropping rate of 3 ml/min, the synthesized ZVI exhibited a narrow range of particle size distribution with a mean size of 3.9 μm, followed by a high surface area, and good catalytic activity. As a catalyst for secondary treatment of the waste cutting fluid, the synthesized ZVI demonstrated a moderate chemical oxygen demand (COD) removal performance of 49%, corresponding to COD reduction for from 4023 mg/l to about 2059 mg/l.

Pt/NiCo2O4 nanowire arrays on Ni foam as catalysts for efficient formaldehyde oxidation at room temperature

Catalytic oxidation of formaldehyde (HCHO) at room temperature is a low-cost and efficient solution for indoor HCHO removal. In this work, NiCo2O4 nanowires were in-situ synthesized on nickel foam (NF) by a simple hydrothermal reaction and then decorated with platinum nanoparticles (NPs). The Pt/NiCo2O4-NF catalyst exhibited excellent HCHO oxidation capacity at ambient temperature, realizing a conversion rate of 90 % within 60 min. The nickel foam substrate prevents the aggregation of NiCo2O4 nanowire arrays. It also enables the growth of large-area and aligned nanowires, contributing to the uniform dispersion of Pt NPs. Moreover, due to the unique redox property and high reactivity of NiCo2O4, numerous surface oxygen vacancies and active oxygen species are generated together with Pt by NaBH4 reduction, which is beneficial to the adsorption and oxidation of HCHO. Moreover, the hierarchical macro-/mesoporous structure of Pt/NiCo2O4-NF facilitates the diffusion of gaseous reactants and provides easily accessible active sites. In contrast with nanosized catalysts, the three-dimensional (3D) Pt/NiCo2O4-NF catalyst possesses high machinability and practicability. This work may shed light on the fabrication of 3D hierarchical catalysts for oxidative HCHO removal and indoor air purification.

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Fabrication of Cu2O/MTiO3 (M = Ca, Sr and Ba) p-n heterojunction for highly enhanced photocatalytic hydrogen generation

Herein, a binary Cu2O/MTiO3 (M = Ca, Sr and Ba) p-n heterojunction composites are successfully designed and prepared by the hydrothermal method and following NaBH4 reduction treatment. With the help of ethanediol and polyvinylpyrrolidone, it is found that Cu2O nanoparticles (NPs) can disperse evenly on the surface of CaTiO3. Excitingly, the highest H2 production rate (HPR) of the Cu2O/CaTiO3 samples is up to 8.268 mmol g−1 h−1, which is about 344.5 times as high as that of CaTiO3 sample under the same conditions. Compared with pure CaTiO3, the photoelectric chemical performance tests manifest that photocurrent density the of Cu2O/CaTiO3 composite increases and the interface resistance decreases. These results manifest that the construction of p-n heterojunction in Cu2O/CaTiO3 sample can improve the separation and migration rates of photogenerated carrier pairs, thus accelerating the generation of H2. Additionally, the Cu2O/CaTiO3 exhibits the best HPR as compared to Cu2O/SrTiO3 and Cu2O/BaTiO3 composites, which may be attributed to the more active sites in hollow CaTiO3. This work reports a viable strategy to fabricate the Cu2O/MTiO3 p-n heterojunction, which can overcome the boundedness of single Cu2O or MTiO3 in photocatalytic performance.

Electrocatalytic conversion of G-type and S-type phenolic compounds from different tree species in a heteropolyacid fluidized system

The electrocatalytic hydrodeoxygenation (ECH) of lignin typical model compounds and lignin-derived oil from different tree species into (alkyl)-cyclohexane and (alkyl)-cyclohexanol in the fluidized electrocatalysis system were investigated in this research. The selected model compounds include two G-type compounds: eugenol (EO) and guaiacol (GO), and two S-type compounds: 4-allyl-2,6-dimethoxyphenol (4-DMP) and 2,6-dimethoxyphenol (2,6-DMP). This ECH system consisted of phosphotungstic acid (PW12) electrolyte, catalyst that suspended in the electrolyte, and NaBH4 reductant in the cathode. The results showed that 4-DMP could be converted using Pt/C as the catalyst at 25 mA/cm2 current density and 80°C for 60 min, with higher faradaic efficiency of 90% and the selectivity of PCH and 4-PCH was 62% and 20%, respectively. For CO bond cleavage, the DFT calculations showed that, for EO, GO, and 4-DMP, the C-OCH3 bond will be firstly broken, while for 2,6-DMP, it is preferred that C-OH bond will be firstly broken. It was found that G-type (EO, GO) was more easily hydrodeoxygenated than S-type (4-DMP, 2,6-DMP) compounds, with the reaction rate in the order of GO > EO > 2,6-DMP > 4-DMP, indicating that the allyl group had a negative effect on the electrocatalytic conversion. Furthermore, it was also found that the complete conversion of lignin-derived oil monomers of pine (mainly G-type) and poplar (mainly S-type) can be achieved, with the yield of target products (PCH and 4-PCH) of 64% and 43%, respectively. Overall, this work innovatively integrates biomass refining and electrocatalytic upgrading, which provides a green and environmentally friendly solution for lignin conversion and utilization.

Precisely controllable oxygen vacancy-manufactured Ov-Co3O4@PPy for high energy density supercapacitor

Effective controllable manufacturing oxygen vacancy and polypyrrole coating can optimize the capacitive and cyclic properties of Co3O4. Herein, composition of Ov-Co3O4@PPy with Co3O4 rich in oxygen vacancy defects and polypyrrole was synthesized using NaBH4 reduction and chronoamperometry. Ov-Co3O4 was synthesized while regulating the concentration of the reducing agent NaBH4 solution, and then Ov-Co3O4@PPy was synthesized by electrodeposition of PPy. The specific capacitance of Ov-Co3O4@PPy formed at an optimal NaBH4 concentration and electrodeposition time was about three times that of Co3O4 without reduction treatment and unwrapped PPy. The capacitance retention rate of Ov-Co3O4@PPy was close to 80.5% after 5000 cycles. In addition, Ov-Co3O4@PPy//AC asymmetric supercapacitor was assembled with the as-prepared Ov-Co3O4@PPy as the positive electrode material and activated carbon as the negative electrode, which yielded specific energy density up to 74.55 Wh kg−1 at 850 W kg−1 power density and a capacitance retention rate close to 110% after 10,000 cycles.

Oxygen Vacancies‐Rich TiO2/C Nanofibers with Boron, Nitrogen Dual‐Doping for Ultrafast Sodium Storage

AbstractTiO2 is an intercalation pseudocapacitive material with low potential and minor structural changes during the sodium storage process. However, the intrinsic electronic conductivity and ionic diffusion kinetics are not unsatisfactory for ultrafast sodium storage. Defect engineering plays a pivotal part in improving the sodium storage kinetics of TiO2 anode materials. Now the common defect regulation methods are complicated. Herein, a simple NaBH4 reduction method is proposed to produce rich oxygen vacancies and boron doping in nitrogen‐doped TiO2/C mesoporous nanofibers, and the finally obtained oxygen vacancies (OVs)‐rich TiO2/C nanofibers (TC‐OVs) also build internal vertical channels. This particular structure of TC‐OVs favors fast transport for electrons and ions, resulting in ultrafast rate capability (156 mAh g−1, 2 A g−1) and long lifespan (139 mAh g−1, 1000 cycles, 1.0 A g−1). The inspiring sodium storage performance of TC‐OVs benefits from the high pseudocapacitance contribution (94%, 5.0 mV s−1). This work provides a method to adjust defects and structures of TiO2 electrode materials for ultrafast chemical energy storage.

NiMoO4 nanorods derives carbon layers wrapped NiCo alloy decorated with Mo2C platinum-based catalyst for efficient methanol electrooxidation

To the aim of accelerate the methanol oxidation reaction (MOR), rationally designing novel MOR catalyst is highly desired. Hence, NiCo alloy resides in carbon layers decorated with Mo2C platinum-based catalyst (Pt/NiCo-Mo2C@NDC) is fabricate. For the fabrication, NiMoO4 nanorods (NRs) are firstly coated with CoZn-ZIF and then subjected to anneal treatment and NaBH4 reduction procedure. In the system, CoZn-ZIF serves as the sacrificial template and reducing agent, rendering bifunctional effect: CoZn-ZIF provides doped nitrogen sources, which are beneficial to the overall conductivity and deposition of Pt nanoparticles. Besides, it could act as the carbon sources for the reaction formation of the Mo2C during high temperature calcination, which delivers the excellent co-catalytic effect. Meanwhile, NiCo alloy can be fabricated during the annealing treatment and alter the structure properties of the catalyst, showing the Ni content-depended electrochemical performance. Therefore, the catalyst exhibits remarkable electrocatalytic activity and stability. Moreover, we also focus on the structure-activity relationships to provide insight into the effect of alloy and molybdenum carbide on catalytic activity.

Bimetallic Pd–Bi nanocatalysts derived from NaBH4 reduction of BiOCl and Pd2+ and exhibit highly efficient hydrogen production over formaldehyde solution

Using liquid formaldehyde as a carrier to obtain clean hydrogen is a promising method. The development of inexpensive catalysts with high activity and stability is crucial for this reaction. Herein, bimetallic Pd–Bi nanocatalysts with different Pd to Bi ratios were prepared through one step in-situ reduction of BiOCl and Pd2+ ions by sodium borohydride (NaBH4). The effect of Pd/Bi ratios and reaction parameters such as formaldehyde concentration and sodium hydroxide concentration on hydrogen production performance were systematically studied. By optimizing the Pd contents in Pd–Bi nanocatalysts under the optimized reaction conditions, an much higher hydrogen (H2) production rate of 472.2 mL min−1g−1 over Pd/BiOCl-3% under 298.15 K can be achieved, which is 4.01 times that of pure Pd nanoparticles (NPs) and much higher than most reported metal-based catalysts.

Preparation of Fe3O4@Fe(0) immobilized enzyme to enhance the efficient degradation of methoxychlor.

The presence of methoxychlor (MXC) in soil and wastewater is considered a nonnegligible environmental threat. Herein, Fe3O4@Fe(0) was obtained by NaBH4 reduction of Fe3O4 nanoparticles and served as a carrier for laccase to construct catalyst. The catalyst was evaluated for the degradation of MXC in treated wastewater and soil with 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) being used as cocatalyst. The removal rate of MXC in wastewater and soil was found to be 89% and 88% in optimum conditions, and the influences of initial MXC concentration, pH, and temperature on the degradation rate were evaluated. The metabolites including 2-methylpentane, 3-methylpentane, and n-pentane of MXC were identified, and possible degradation mechanisms were proposed. Overall, this work successfully demonstrates not only the ability to degrade MXC in different circumstances but also provides a new idea for environmental remediation in the future.

Synthesis of 3-Aryl-Substituted 4-Aminopyrazoles from Acetophenones

AbstractA synthetic methodology for a protecting-group-free formation of 3-aryl-substituted 4-aminopyrazoles from acetophenones via a telescoped oximation and hydrazine condensation of 1,3-ketoaldehydes to generate nitrosopyrazoles, and copper-catalyzed NaBH4 reduction of the nitroso group, was demonstrated. The synthesis tolerates a broad scope of substrates with a variety of substituents on the phenyl ring to afford the desired products.

Excellent Catalytic Performance of Ce–MOF with Abundant Oxygen Vacancies Supported Noble Metal Pt in the Oxidation of Toluene

Metal organic framework (MOF) is a type of porous organic material. In this work, three catalysts loaded with noble metal Pt were prepared by NaBH4 reduction method with three different morphologies of Ce–MOF as carriers. Their physicochemical properties were characterized by XRD, Raman, FTIR, N2 adsorption, SEM, XPS, and TGA. The catalytic performances of different catalysts were evaluated via toluene oxidation and CO2 selectivity. Rod–shaped Pt/MOF–BTC exhibited best catalytic performance compared to Pt/MOF–808 and Pt/UiO–66, its T50 and T90 were 140 °C and 149 °C, respectively. After deducting the effect of specific surface, Pt/MOF–BTC still had the lowest apparent activation energy (62.8 kJ·mol−1), which is due to the abundant atomic Pt and oxygen vacancy content on its surface. After the reaction, the structure of Pt/MOF–BTC may become amorphous according to XRD results. Furthermore, the presence of amorphous structure had no effect on the catalytic activity of the catalyst. In the stability test of Pt/MOF–BTC to toluene oxidation, both toluene conversion and CO2 selectivity remained at 100%, and remained stable for 11 h. Moreover, Pt/MOF–BTC also had better resistance to high weight hourly space velocity (WHSV) or water resistance. The catalyst maintained high catalytic activity for 3 times reusability. This study provides valuable experience for the future work of MOF in the field of VOC catalytic oxidation.

Tailoring the Fenton-like mechanisms of surface functional groups by corrosive structural defects for superior pollutant degradation on platform carbon

The high abundance, low cost and no toxicity of solid catalyst play governing roles in Fenton-like catalysis via non-radical pathways. Reactive carbons exhibit low capacity for PMS activation and pollutant degradation, although they possess unique material properties. Herein, a simple and efficient two-step strategy of “chemical reduction + acidic corrosion” was proposed and validated to refine platform carbon for Fenton-like catalysis in environmental decontamination. Platform carbon treated by NaBH4 reduction and H2SO4 corrosion exhibited much superior reactivity and selectivity as well as stability for PMS activation to degrade phenolic pollutants in various water matrix. Effects of tailoring condition, catalyst dosage, pollutant concentration, pH range and PMS concentration were studied. Control tests with other catalysts, catalyst reusability and technical applicability were carried out. Reaction mechanisms were elucidated by ESR and radical quenching as well as electrochemical tests. Radical pathway was not a critical role, while catalysis was controlled by catalyst-oxidant surface interactions and non-radical pathways (1O2 and electron transfer), the latter played the dominant role mediated by surface CO group. Our findings provided a new chance to utilize platform carbon and other inert materials in selective Fenton-like catalysis for safe water purification.

Photocatalytic activity of defective black-titanium oxide photocatalysts towards pesticide degradation under UV/VIS irradiation

Wastewater treatment containing pesticides has become an intensively studied field in recent years. Titanium dioxide is the most efficient photocatalyst that uses UV radiation, but the photocatalytic properties can be improved under visible radiation conditions. The photocatalytic properties of titanium oxide are closely related to materials defect disorders, such as oxygen vacancy and Ti3+ defect. Therefore, defective TiO2 or black TiO2 nanoparticles are attractive materials for heterogeneous photocatalysis. Defective nanoparticles with superior properties to white TiO2 and efficient solar harvest in the photocatalytic application were synthesised in two convenient and low-cost steps via facile sol-gel and NaBH4 reduction techniques. In the reduction step of the white titanium dioxide powder, the defects were controlled by varying the TiO2: NaBH4wt ratio at 350 °C for 1 h in an argon atmosphere, obtaining powders with shades of grey to black. The characterisation measurements include structure (XRD, XPS, EDS), morphology (SEM), optical properties (UV–vis DRS spectra), and particles (surface area, porosity, DLS particle size distribution) were applied to investigate the properties of nanostructured defective TiO2. EDS analysis revealed that the O: Ti ratio for the white TiO2 powder sample was approximately 1.7, which decreased from 1.7 to 1.6 and 1.4 as the TiO2:NaBH4 ratio was 4:1, 2:1 and 1:1, respectively. Photocatalytic activity of black titanium oxide under visible light was over 90% of imidacloprid degradation and can be associated with the specific surface area, bandgap energy smaller than white TiO2, a large amount of surface defect Ti3+ and oxygen vacancies that promote charge carriers' separation.