O2 Nanosheets Research Articles

Surface Optimization of Noble-Metal-Free Conductive [Mn1/4Co1/2Ni1/4]O2 Nanosheets for Boosting Their Efficacy as Hybridization Matrices.

Conductive 2D nanosheets have evoked tremendous scientific efforts because of their high efficiency as hybridization matrices for improving diverse functionalities of nanostructured materials. To address the problems posed by previously reported conductive nanosheets like poorly-interacting graphene and cost-ineffective RuO2 nanosheets, economically feasible noble-metal-free conductive [MnxCo1-2xNix]O2 oxide nanosheets are synthesized with outstanding interfacial interaction capability. The surface-optimized [Mn1/4Co1/2Ni1/4]O2 nanosheets outperformed RuO2/graphene nanosheets as hybridization matrices in exploring high-performance visible-light-active (λ>420nm) photocatalysts. The most efficient g-C3N4-[Mn1/4Co1/2Ni1/4]O2 nanohybrid exhibited unusually high photocatalytic activity (NH4 + formation rate: 1.2mmol g-1 h-1), i.e., one of the highest N2 reduction efficiencies. The outstanding hybridization effect of the defective [Mn1/4Co1/2Ni1/4]O2 nanosheets is attributed to the optimization of surface bonding character and electronic structure, allowing for improved interfacial coordination bonding with g-C3N4 at the defect sites. Results from spectroscopic measurements and theoretical calculations reveal that hybridization helps optimize the bandgap energy, and improves charge separation, N2 adsorptivity, and surface reactivity. The universality of the [Mn1/4Co1/2Ni1/4]O2 nanosheet as versatile hybridization matrices is corroborated by the improvement in the electrocatalytic activity of hybridized Co-Fe-LDH as well as the photocatalytic hydrogen production ability of hybridized CdS.

Molten salt method for preparing Mn0.3Ru0.7O2 nanosheets as a superior bifunctional catalyst for rechargeable zinc-air batteries

Integrating components for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) while optimizing their electronic structure is an effective strategy for developing excellent bifunctional catalysts for rechargeable zinc-air batteries (ZABs). In this study, we successfully fabricated Mn0.3Ru0.7O2 nanosheets based on a solid solution oxide using a simple molten salt method. The Mn0.3Ru0.7O2 nanosheets exhibits abundant Ru and Mn sites through the Ru-O-Mn structure, which serve as excellent OER and ORR active centers. Experimental and theoretical studies validate the coccurrence of charge transefer between the Ru-O-Mn bond, modulating the valence state and d-band center of the Mn and Ru, thereby subsequently improving their ORR/OER intrinsic activity. Remarkably, the Mn0.3Ru0.7O2 nanosheets displays superior electropcatalytic performance with a charge/discharge voltage gap (ΔE) of only 0.59 V, which is the best among all reported counterpart catalysts. A rechargeable ZAB utilizing Mn0.3Ru0.7O2 nanosheets achieved a power density of 154 mW cm−2 and a specific capacity of 821 mA h g−1, surpassing that of the commercial Pt/C + RuO2 mixing catalyst. This study offers a new strategy for preparing highly active and durable bifunctional catalysts for rechargeable ZABs.

Facile and efficient fabrication of Cu1.04Mn0.96O2 nanosheet anodes with superior electrochemical lithium storage capability

In this work, Cu1.04Mn0.96O2 nanosheets were synthesized via a simple hydrothermal method, and their electrochemical lithium storage properties and reaction mechanisms were investigated. The nanosheet structure effectively promotes electron transfer and shortens the transport path. Additionally, the partial substitution of Cu for Mn decreases the Jahn-Teller distortion of the MnO6 octahedron. Employing as an anode for Li-ion batteries, the specific capacity reached 610.91 mAh g−1 after 100 cycles at a current density of 100 mA g−1.

Inkjet Printing of Long-Range Ordering Two-Dimensional Magnetic Ti0.8Co0.2O2 Film.

The value of two-dimensional (2D) materials in printed electronics has been gradually explored, and the rheological properties of 2D material dispersions are very different for various printing technologies. Understanding the rheological properties of 2D material dispersions plays a vital role in selecting the optimal manufacturing technology. Inkjet printing is suitable for small nanosheet sizes and low solution viscosity, and it has a significant advantage in developing nanosheet inks because of its masklessness, high efficiency, and high precision. In this work, we selected 2D Ti0.8Co0.2O2 nanosheets, which can be synthesized in large quantities by the liquid phase exfoliation technique; investigated the effects of nanosheet particle size, solution concentration on the rheological properties of the dispersion; and obtained the optimal printing processing method of the dispersion as inkjet printing. The ultrathin Ti0.8Co0.2O2 nanosheet films were prepared by inkjet printing, and their magnetic characteristics were compared with those of Ti0.8Co0.2O2 powder. The films prepared by inkjet printing exhibited long-range ordering, maintaining the nanosheet powders' paramagnetic characteristics. Our work underscored the potential of inkjet printing as a promising method for fabricating precisely controlled thin films using 2D materials, with applications spanning electronics, sensors, and catalysis.

General Scalable Synthesis of Mesoporous Metal Oxide Nanosheets with High Crystallinity for Ultralong‐Life Li–S Batteries

AbstractMesoporous metal oxide nanosheets (MMONs) are demonstrated great promise for various catalytic applications such as water splitting, CO2 reduction, and metal–sulfur batteries. However, limited by the conventional high‐temperature synthetic routes, the prepared MMONs expose only a small portion of the effective catalytic sites, which greatly restricts their electrocatalytic activity. Herein, a facile and general glycine‐assisted strategy is developed to synthesize a series of MMONs with high crystallinity and remarkable porosity. Impressively, single‐phase perovskite type MMONs containing up to ten metal cations can be synthesized easily using this method without any further purification step. As a proof of concept, the Li–S cell with mesoporous LaFe0.4Co0.2Ni0.2Cu0.2O3 nanosheets as catalyst achieves superior ultralong cycling life over 1500 cycles at 2 C with only 0.041% capacity decay per cycle and a high areal capacity reaching 6.0 mAh cm−2 at a low electrolyte/sulfur ratio of 5.9 µL mg−1. The improved performance is attributed to abundant active sites and synergistic contribution of multicomponent. This work paves a new avenue for the general synthesis of advanced MMONs and will inspire the practical applications in different fields.

Hetero-assembly design of 2D oxide nanosheets for tailored thermal shielding materials

We present a new approach for designing thermal shielding materials using two-dimensional oxide nanosheets. Our approach uses hetero-assembly design [(Ti0.87O2) m (Cs2.7W11O35−d )20 (m = 0, 5, 10)] by overlaying high refractive index (n) Ti0.87O2 nanosheets with transparent conducting Cs2.7W11O35−d nanosheets. Through proper design of the thickness of high-n Ti0.87O2 layers, we achieved the optimum thermal shielding properties with a high NIR reflectance (>46%), a high visible transparency (>76%) and a neutral color in an ultrathin form (<60 nm). Our nanosheet approach is of technological importance for exploring new thermal shielding materials.

Binder-Free LiMn2 O4 Nanosheets on Carbon Cloth for Selective Lithium Extraction from Brine via Capacitive Deionization.

In this study, a three-step strategy including electrochemical cathode deposition, self-oxidation, and hydrothermal reaction is applied to prepare the LiMn2 O4 nanosheets on carbon cloth (LMOns@CC) as a binder-free cathode in a hybrid capacitive deionization (CDI) cell for selectively extracting lithium from salt-lake brine. The binder-free LMOns@CC electrodes are constructed from dozens of 2D LiMn2 O4 nanosheets on carbon cloth substrates, resulting in a uniform 2D array of highly ordered nanosheets with hierarchical nanostructure. The charge/discharge process of the LMOns@CC electrode demonstrates that visible redox peaks and high pseudocapacitive contribution rates endow the LMOns@CC cathode with a maximum Li+ ion electrosorption capacity of 4.71mmol g-1 at 1.2V. Moreover, the LMOns@CC electrode performs outstanding cycling stability with a high-capacity retention rate of 97.4% and a manganese mass dissolution rate of 0.35% over ten absorption-desorption cycles. The density functional theory (DFT) theoretical calculations verify that the Li+ selectivity of the LMOns@CC electrode is attributed to the greater adsorption energy of Li+ ions than other ions. Finally, the selective extraction performance of Li+ ions in natural Tibet salt lake brine reveals that the LMOns@CC has selectivity ( = 7.48) and excellent cycling stability (100 cycles), which would make it a candidate electrode for lithium extraction from salt lakes.

Phase Engineering of 2D Spinel-Type Manganese Oxides.

2D magnetic materials have been of interest due to their unique long-range magnetic ordering in the low-dimensional regime and potential applications in spintronics. Currently, most studies are focused on strippable van der Waals magnetic materials with layered structures, which typically suffer from a poor stability and scarce species. Spinel oxides have a good environmental stability and rich magnetic properties. However, the isotropic bonding and close-packed nonlayered crystal structure make their 2D growth challenging, let alone the phase engineering. Herein, a phase-controllable synthesis of 2D single-crystalline spinel-type oxides is reported. Using the van der Waals epitaxy strategy, the thicknesses of the obtained tetragonal and hexagonal manganese oxide (Mn3 O4 ) nanosheets can be tuned down to 7.1nm and one unit cell (0.7nm), respectively. The magnetic properties of these two phases are evaluated using vibrating-sample magnetometry and first-principle calculations. Both structures exhibit a Curie temperature of 48 K. Owing to its ultrathin geometry, the Mn3 O4 nanosheet exhibits a superior ultraviolet detection performance with an ultralow noise power density of 0.126 pA Hz-1/2 . This study broadens the range of 2D magnetic semiconductors and highlights their potential applications in future information devices.

Structural, optical, and electrical properties of cellulose/titanate nanosheets composite with enhanced protection against gamma irradiation

Two-dimensional (2D) materials have emerged as a promising functional filler in nanocomposites due to their unique anisotropy and resilience to harsh conditions. We report herein the use of Ti0.91O2 nanosheets as a protective component against γ-irradiation to cellulose paper. The titanate nanosheets were prepared via a sequence of solid-state synthesis of lepidocrocite-type Cs0.7Ti1.825O4, proton exchange to H0.7Ti1.825O4·H2O, and exfoliation with tetrabutylammonium hydroxide. The nanosheets were incorporated into the commercial cellulose filter paper by a simple dip coating up to 0.6 mg cm−2, equivalent to 10 wt% TiO2. The nanosheets distribution was demonstrated by energy dispersive X-ray (EDX) mapping, synchrotron radiation X-ray tomographic microscopy (SRXTM), and atomic force microscopy (AFM). It is found that γ-irradiation (up to 50 kGy) destroyed the cellulose Iβ crystallinity of uncoated paper, but this is less pronounced in the cellulose/titanate nanosheets composite. This was also confirmed by the lack of a 235 nm-absorption characteristics of irradiation-induced decomposition product(s) in nanosheets-containing papers, which also exhibit UVA shielding property. The coated samples remained white while the uncoated ones were darkened with γ-irradiation. In addition, the nanosheets-coated papers showed dielectric permittivity, loss tangent, and AC conductivity which were invariant of the γ-dose, unlike those from the uncoated ones. Our work demonstrates the use of lead-free Ti0.91O2 nanosheets as a γ-shielding component to slow down/prevent structural, optical, and electrical properties damages in cellulose paper, which could extend to other nature-derived materials.

Selective CO2 Electroreduction to Formate on Polypyrrole-Modified Oxygen Vacancy-Rich Bi2 O3 Nanosheet Precatalysts by Local Microenvironment Modulation.

Challenges remain in the development of highly efficient catalysts for selective electrochemical transformation of carbon dioxide (CO2 ) to high-valued hydrocarbons. In this study, oxygen vacancy-rich Bi2 O3 nanosheets coated with polypyrrole (Bi2 O3 @PPy NSs) are designed and synthesized, as precatalysts for selective electrocatalytic CO2 reduction to formate. Systematic material characterization demonstrated that Bi2 O3 @PPy precatalyst can evolveintoBi2 O2 CO3 @PPy nanosheets with rich oxygen vacancies (Bi2 O2 CO3 @PPy NSs) via electrolyte-mediated conversion and function as the real active catalyst for CO2 reduction reaction electrocatalysis. Coating catalyst with a PPy shell can modulate the interfacial microenvironment of active sites, which work in coordination with rich oxygen vacancies in Bi2 O2 CO3 and efficiently mediate directional selective CO2 reduction toward formate formation. With the fine-tuning of interfacial microenvironment, the optimized Bi2 O3 @PPy-2 NSs derived Bi2 O2 CO3 @PPy-2 NSs exhibit a maximum Faradaic efficiency of 95.8% at -0.8V (versus.reversible hydrogen electrode) for formate production. This work might shed some light on designing advanced catalysts toward selective electrocatalytic CO2 reduction through local microenvironment engineering.

Molecularly Thin BaTiO3 Nanosheets with Stable Ferroelectric Response (Adv. Electron. Mater. 4/2023)

Molecularly Thin Perovskite Ferroelectric Two-dimensional (2D) Ti0.87O2 nanosheets can serve as templates, guiding the low temperature synthesis of 2D BaTiO3 nanosheets with a molecularly thin thickness (<3 nm). The 1.8-nm thick BaTiO3 nanosheet is the thinnest free-standing perovskite to experimentally confirm ferroelectricity so far. More details can be found in article number 2201239 by Minoru Osada and co-workers.

Automated One-Drop Assembly for Facile 2D Film Deposition.

The effective application of 2D materials is strongly dependent on the mass production of high-quality large-area 2D thin films. Here, we demonstrate a strategy for the automated manufacturing of high-quality 2D thin films using a modified drop-casting approach. Our approach is simple; by using an automated pipette, a dilute aqueous suspension is dropped onto a substrate heated on a hotplate, and controlled convection by Marangoni flow and liquid removal causes the nanosheets to come together to form a tile-like monolayer film in 1-2 min. Ti0.87O2 nanosheets are utilized as a model system for investigating the control parameters such as concentrations, suction speeds, and substrate temperatures. We perform the automated one-drop assembly of a range of 2D nanosheets (metal oxides, graphene oxide, and hexagonal boron nitride) and successfully fabricate various functional thin films in multilayered, heterostructured, and sub-micrometer-thick forms. Our deposition method enables on-demand large-size (>2 inchϕ) manufacturing of high-quality 2D thin films while reducing the time and sample consumption.

Au Nanowires Decorated Ultrathin Co3 O4 Nanosheets toward Light-Enhanced Nitrate Electroreduction.

Nitrate is a reasonable alternative instead of nitrogen for ammonia production due to the low bond energy, large water-solubility, and high chemical polarity for good absorption. Nitrate electroreduction reaction (NO3 RR) is an effective and green strategy for both nitrate treatment and ammonia production. As an electrochemical reaction, the NO3 RR requires an efficient electrocatalyst for achieving high activity and selectivity. Inspired by the enhancement effect of heterostructure on electrocatalysis, Au nanowires decorated ultrathin Co3 O4 nanosheets (Co3 O4 -NS/Au-NWs) nanohybrids are proposed for improving the efficiency of nitrate-to-ammonia electroreduction. Theoretical calculation reveals that Au heteroatoms can effectively adjust the electron structure of Co active centers and reduce the energy barrier of the determining step (*NO → *NOH) during NO3 RR. As the result, the Co3 O4 -NS/Au-NWs nanohybrids achieve an outstanding catalytic performance with high yield rate (2.661mg h-1 mgcat -1 ) toward nitrate-to-ammonia. Importantly, the Co3 O4 -NS/Au-NWs nanohybrids show an obviously plasmon-promoted activity for NO3 RR due to the localized surface plasmon resonance(LSPR) property of Au-NWs, which can achieve an enhanced NH3 yield rate of 4.045mg h-1 mgcat -1 . This study reveals the structure-activity relationship of heterostructure and LSPR-promotion effect toward NO3 RR, which provide an efficient nitrate-to-ammonia reduction with high efficiency.

A two-dimensional cation-deficient Ti0.87O2 artificial protection layer for stable sodium metal anodes

The practical application of sodium (Na) metal batteries is still hampered by uncontrolled Na dendrite growth and unstable solid-electrolyte interphase (SEI), which lead to poor cycling stability and even serious safety concerns. Here, we present a dendrite-free and highly stable Na metal anode via directly transferring a cation-deficient Ti0.87O2 nanosheet constructed artificial layer onto Na surface. Profiting from the sodiophilic nature and high Young's modulus, the Ti0.87O2 layer can seamlessly connect to the Na surface and avoid the layer fracture caused by Na volume changes. In addition, the existence of cation defects enables Ti0.87O2 layer with strong Na+ adsorption ability that pre-uniforms the Na+ flux. Further, the Ti0.87O2 protection layer has high ionic conductivity but poor electronic conductivity; this allows Na+ quasi self-diffusion but restricts Na plating under the protection layer. With these advantages, the Ti0.87O2 layer stabilizes the electrolyte/electrode interface and guarantees dendrite-free plating/stripping of Na. As a result, significantly improved performance of the symmetric batteries and Na3V2(PO4)3 based full cells has been obtained. Importantly, the Ti0.87O2 layer can also protect Li anodes and further enhance their performance. Our work presents a new versatile strategy that brings metal based anodes one step closer to being a viable technology.

Ir-CoO Active Centers Supported on Porous Al2 O3 Nanosheets as Efficient and Durable Photo-Thermal Catalysts for CO2 Conversion.

Photo-thermal catalytic CO2 hydrogenation is currently extensively studied as one of the most promising approaches for the conversion of CO2 into value-added chemicals under mild conditions; however, achieving desirable conversion efficiency and target product selectivity remains challenging. Herein, the fabrication of Ir-CoO/Al2 O3 catalysts derived from Ir/CoAl LDH composites is reported for photo-thermal CO2 methanation, which consist of Ir-CoO ensembles as active centers that are evenly anchored on amorphous Al2 O3 nanosheets. A CH4 production rate of 128.9 mmol gcat⁻ 1 h⁻1 is achieved at 250 °C under ambient pressure and visible light irradiation, outperforming most reported metal-based catalysts. Mechanism studies based on density functional theory (DFT) calculations and numerical simulations reveal that the CoO nanoparticles function as photocatalysts to donate electrons for Ir nanoparticles and meanwhile act as "nanoheaters" to effectively elevate the local temperature around Ir active sites, thus promoting the adsorption, activation, and conversion of reactant molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) demonstrates that illumination also efficiently boosts the conversion of formate intermediates. The mechanism of dual functions of photothermal semiconductors as photocatalysts for electron donation and as nano-heaters for local temperature enhancement provides new insight in the exploration for efficient photo-thermal catalysts.

Atomic-scale engineering of cation vacancies in two-dimensional unilamellar metal oxide nanosheets for electricity generation from water evaporation

Water evaporation-induced electricity generation, as an emerging energy harvesting technology, has recently attracted extensive attention owing to its ability to harvest electricity directly from the natural water evaporation process. However, the crucial issue that has restricted its practical applications is the low power density and conversion efficiency presented thus far, which generally originated from the weak water-solid interaction between evaporation-induced water flow and nanostructured materials. Exploration of a regulatory approach that can enhance water-solid interaction at an atomic level is highly demanded. Herein, we propose the Ti vacancy engineering at the atomic scale in two-dimensional (2D) unilamellar titanium oxide (Ti1−δO2) nanosheets for efficient water evaporation-induced electricity generation. 2D Ti0.87O2 and Ti0.91O2 nanosheets with precisely controlled concentrations of Ti atomic vacancies are rationally designed. The water flow passes through the 2D gallery of nanosheets while the Ti atomic vacancies can effectively enhance the water-solid interaction between Ti1−δO2 nanosheets and water flow during the water evaporation process for electricity generation. As a result, a stable open-circuit voltage of ∼1.32 V for the hydrovoltaic device made of Ti0.87O2 nanosheets can be maintained for more than 250 h, outperforming those for the commercial TiO2 and Ti0.91O2 nanosheets. This work indicates a promising way to utilize defective 2D materials for hydrovoltaic technology.

Stabilizing Single-Atomic Pt by Forming PtFe Bonds for Efficient Diboration of Alkynes.

Precisely tailoring the oxidation state of single-atomic metal in heterogeneous catalysis is an efficient way to stabilize the single-atomic site and promote their activity, but realizing this approach remains a grand challenge to date. Herein, a class of stable single-atomic catalysts with well-tuned oxidation state of Pt by forming PtFe atomic bondsisreported, which are supported by defective Fe2 O3 nanosheets on reduced graphene oxide (PFARFNs). These as-synthesized materials can greatly enhance the catalytic activity, stability, and selectivity for the diboration of alkynes. The PFARFNs exhibit high conversion of 99% at 100°C with an outstanding turnover frequency (TOF) of 545h-1 , and a relatively high conversion of 58% at room temperature (25°C) with a TOF of 310h-1 , which has beenhardly achieved previously. Through both experimental and theoretical investigation, it is demonstrated that the fast electron transfer from Fe to Pt in Fe-Pt-O atomic sites in PFARFNs can not only stabilize the single-atomic Pt, but also significantly improve their catalytic activity.

Molecularly Thin BaTiO3 Nanosheets with Stable Ferroelectric Response

Abstract2D ferroelectrics provide great promise for future electronics owing to their unique properties at 2D limit. Although simple perovskite oxides (such as BaTiO3 and PbTiO3) are an important target for 2D ferroelectrics, controlled synthesis of 2D nanosheets still remains a challenge. Here, this issue is addressed by using a new chemical protocol; unilamellar Ti0.87O2 nanosheets can serve as templates, guiding the solvothermal synthesis of 2D BaTiO3 nanosheets with a molecularly thin thickness (&lt; 3 nm). Raman spectroscopy, second‐harmonic generation, and transmission electron microscopy characterizations suggest the formation of tetragonal ferroelectric BaTiO3 nanosheets. Based on piezoresponse force microscopy, BaTiO3 nanosheets exhibit a clear ferroelectric response with a high Curie temperature (≈100 °C) even down to 1.8 nm thickness. This study provides new opportunities to investigate perovskite ferroelectrics with the critical thickness.

A novel two-dimensional superconducting Ti layer: density functional theory and electron-beam irradiation.

Since the discovery of graphene in an atomic thin layer format, many investigations have been conducted to search for two-dimensional (2D) layered materials, in which 3d-transition metals offer much new physics and great freedom of tunability. In this work, through electron-beam irradiation, we enable the manufacture of a new 2D Ti nanosheet from a suspension of Ti0.91O2 nanosheets. In state-of-the-art density functional theory (DFT), both empirical and linear response theory predicted that Hubbard Ueff values would be imposed, resulting in unstable phonon dispersion curves. In the end, the newly found Ti monolayer is confirmed to be a non-magnetic superconductor, with a medium level of electron-phonon coupling. The newly established Ti layer is quite robust under strain, and the evolution of local Dirac points in electronic bands is also analyzed in terms of linearity and energetic shift near the Fermi energy. As suggested by the Fermi surface, this metal monolayer experiences an electronic topological transition under strain. Our findings will encourage many more explorations of pure d metal-based isotopic monolayers with diverse structures and open a new playground for 2D superconductors and ultra-thin sensoring components.

A novel Co1.29Ni1.71O4/glycerolate-derived oxygen-vacancies-containing TiO2 composite for highly efficient photocatalytic hydrogen evolution

Charge separation and migration is still a big challenge for photocatalysis. Constructing heterojunction interface structure is a useful way to improve charge separation efficiency. Here, a novel glycerolate-derived n-type TiO2 with oxygen vacancies was hybridized with Co1.29Ni1.71O4 by a facial ultrasonication method to achieve such a purpose. The optimized 2.5 % Co1.29Ni1.71O4/TiO2 hybrid showed a photocatalytic hydrogen evolution rate of 1685 μmol g−1 h−1 under 365 nm LED light irradiation, 26.7-fold higher than that of pure TiO2 (63 μmol g−1 h−1). Besides, the hydrogen production amount kept a linear increase with the increase of irradiation time for the 2.5%Co1.29Ni1.71O4/TiO2 catalyst during a 24 h-long continuous hydrogen release test, confirming the excellent catalytic stability. Detailed characterizations demonstrated that Co1.29Ni1.71O4 nanosheet was closely contacted with TiO2 nanoparticles, which increases specific surface area and widens the light absorption window of TiO2. Moreover, Co1.29Ni1.71O4 addition facilitated highly efficient separation of photogenerated carriers and prolongs lifetimes of the excited electrons. First principles calculations confirmed that there existed strong interaction between Co1.29Ni1.71O4 and TiO2 in the composite, and electrons were directly transferred from Co1.29Ni1.71O4 to TiO2 at the interface by the Ni-O and Co-O pathway. All of these leaded to a high photocatalytic hydrogen evolution activity for the Co1.29Ni1.71O4/TiO2 composite. This work revealed Co1.29Ni1.71O4 to be a promising heterojunction counterpart material and able to promote photocatalysis through unique cross-boundary charge transfer.