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Encapsulation of Cu nanoparticles by carbon chain mail is a promising approach to extend the service endurance. However, the diffusion of oxygen across the surfaces and interfaces of Cu nanoparticles (NPs) may induce obvious changes to their surface compositions, thereby dramatically altering catalytic properties. Here we reported an unanticipated boosting catalytic activity of graphitic chain mail-encapsulated Cu nanocatalysts (1.3- to 6.8-fold enhancement from initial 1.6–13.4 s−1g−1 to stable 6.6–21.5 s−1g−1) for the reduction of 4-nitrophenol by simply immersing these NPs in water for 10 days without any further treatment. The graphitic shells were arc-converted from sixteen types of biomass residuals and polymeric wastes. The rising catalytic activity was attributed to the temporal formation of Cu 2 O at the interface of Cu core and graphite shell, which was derived from the diffusion of dissolved oxygen across the defective graphitic chain mail. The increment of catalytic activity was linearly related with the rising content of Cu 2 O. The monotonous relations of initial and enhanced activities with shell thickness and interfacial composition of NPs were also well established. This work provides a new insight into the interfacial manipulation of core/shell nanocatalysts, and paves a versatile path for the high value-added utilization of carbon wastes. [Display omitted] [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of carbon dioxide to CO by reverse water gas shift reaction plays a vital role in the recycling of the abundant carbon source. Here, the reaction over a series of zeolite L-supported platinum catalysts was systematically investigated to study the promoting role of potassium. The results of activity tests showed that controlled addition of potassium promoter to Pt/L catalyst was beneficial for the catalytic activity and selectivity. It was observed that cage encapsulation by zeolite pores could stabilize Pt nano-particles even at severe reaction conditions. Furthermore, X-ray absorption near edge structure and X-ray photoelectron spectra results demonstrated that the chemical state of platinum was altered by the additional potassium promoter, providing evidence for the formation of Pt-O(OH)-K interfacial sites. Thereafter, the Pt-O(OH)-K interfaces, acting as main active sites to adsorb CO 2 and produce bridge-bonded formate intermediates, were identified by a set of in-situ diffuse reflectance Fourier transform infrared spectroscopy and microcalorimetry measurements. This finding provides new insights into the use of a variety of zeolite as carriers for highly dispersed noble metal in catalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

Recently, to improve the catalytic activity of oxygen evolution reaction (OER) electrocatalysts, some design strategies, such as the decrease of the catalyst particle size, the formation of the porous structure and the couple of carbon-based materials, are receiving increased attention in energy-related systems. Herein, based on metal organic framework (MOF), we develop an effective strategy to synthesize Ni nanoparticles embedded in N doped carbon nanotubes (Ni NPs@N-CNTs) catalyst. In consequence, the Ni NPs@N-CNTs integrates the advantageous features of NPs and N-CNTs towards OER, such as more catalytic sites, large surface area, pore-rich structure and good electrical conductivity. Benefiting from the favorable features, the Ni NPs@N-CNTs exhibits a better OER performance than commercial RuO 2 in alkaline medium, which includes a lower onset potential (1.49 V), a smaller Tafel slope (106 mV dec −1 ). The present work opens a new window for the construction of the coupling materials between NPs and carbon-based materials to increase the electrocatalytic activity of transition metal catalysts. [ABSTRACT FROM AUTHOR]

Interfacial charge transfer efficiency and electronic states of active sites are two essential issues to restrict catalytic activity of electrocatalysts for oxygen evolution reaction (OER). In this work, we show that although Au is recognized to be inert towards OER, the catalytic activity of Fe 3 O 4 catalyst for OER was highly boosted by coupling Fe 3 O 4 with Au to address these two issues. Here, Au nanoparticles were attached to hierarchical Fe 3 O 4 microsphere through electrochemical deposition, a mild and rapid approach that can be accomplished within 3 min and requires no sophisticated equipment. With the coupling of Au, interfacial charge transfer resistance of Fe 3 O 4 declined remarkably. On the other hand, oxidability of Fe sites and electron accepting capability of Au sites was elevated due to strong interaction between Au and Fe 3 O 4. Owing to these two merits induced by Au, Fe 3 O 4 exhibited enhanced catalytic activity for OER. The potential of Fe 3 O 4 to obtain 10 mA/cm2 decreased by 640 mV, the current density was amplified up to 2.5 fold at the potential of 2 V (vs SCE), and the Tafel slop was reduced by 146 mV/dec. This work shows that the catalytic activity of an earth-abundant electrocatalyst (Fe 3 O 4) for OER reaction was boosted by coupling it with OER-inert Au. It is found that the coupling of Au not only facilitated charge transfer efficiency of the catalyst, but elevated the oxidability of Fe sites and electron accepting capability of Au sites. Thereby, when coupled with Au, Fe 3 O 4 exhibited enhanced current density, reduced overpotential, and smaller Tafel slop. [Display omitted] • Enhance catalytic activity of Fe 3 O 4 for OER reaction via coupling of OER-inert Au. • Effectively promoted interfacial charge transfer with the decoration of Au. • Modify the state of Fe sites and Au sites by strong interaction of Au with Fe 3 O 4. • An easy-to-handle and rapid way to couple Au with hierarchical Fe 3 O 4 microspheres. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Co 3 O 4 -SnO 2 composite was successfully fabricated by annealing the bimetallic oxalates. • SnO 2 as a cocatalyst was indispensable for the improvement of catalytic activity of Co 3 O 4. • The synergy of SnO 2 and Co 3 O 4 afforded the Co 3 O 4 -SnO 2 composite with higher catalytic activity. • The Co 3 O 4 -SnO 2 composite exhibited excellent stability and reusability in PMS activation. • SO 4 •−, •OH, O 2 •−, and 1O 2 jointly contributed to the fast elimination of CAP. In this study, the Co 3 O 4 -SnO 2 composite derived from bimetallic oxalates was rationally fabricated and utilized as a catalyst for peroxymonosulfate (PMS) activation towards the destruction of chloramphenicol (CAP). The physicochemical properties of the Co 3 O 4 -SnO 2 were systematically characterized to discover the relationship between its structure and catalytic performance. SnO 2 as a cocatalyst with high conductivity and stability immensely improved the activity of Co 3 O 4 in the Co 3 O 4 -SnO 2 composite. Approximately 98% of CAP (10 mg/L) was eliminated by the Co 3 O 4 -SnO 2 (0.1 g/L) activated PMS (1.0 mmol/L) at initial pH 7 within 20 min. The rationally designed Co 3 O 4 -SnO 2 composite exhibited higher catalytic activity than Co 3 O 4 , SnO 2 , and other cobalt-based bimetallic oxides (such as Co-Fe, Co-Mn, and Co-Cu) in the PMS activation for the CAP degradation. The synergistic effect of Co 3 O 4 and SnO 2 endowed the Co 3 O 4 -SnO 2 composite with higher conductivity and more electron transfer, which was proved by the electrochemical tests. The presence of SO 4 •−, •OH, O 2 •−, and 1O 2 during the CAP degradation was testified by both quenching experiments and electron paramagnetic resonance (EPR) spectroscopy. In addition, the catalytic mechanism and degradation pathways were further proposed via the characterization of X-ray photoelectron spectroscopy (XPS) and the identification of transformation products, respectively. This work provides a new insight into the preparation of novel catalysts and their application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is considered as a promising approach to storing renewable electricity in the form of hydrogen fuel. In this work, we report the design and electrocatalytic properties of chiral CuO@Ni with three dimensional (3D) continuous macroporous framework. With the chiral CuO@Ni as anode, the OER overpotential required to achieve the current density of 10 mA/cm2 was as low as 110 mV in 0.1 M KOH electrolyte, and the hydrogen production rate of water splitting reaction could reach 1070 nL/s. Moreover, the OER overpotential could be regulated easily by controlling the deposition time of chiral CuO layer on Ni. The high catalytic activity of chiral CuO@Ni for water splitting is closely associated with the Chiral-induced spin selectivity ( CISS ) effect, the large reactive area provided by its 3D macroporous structure, and the effective cooperation between chiral CuO and Ni foam that facilitated the transportation of spin aligned electrons from chiral CuO layer to Ni. The results shown in this work indicate a simple and promising strategy to improve the electrocatalytic activity of other chiral earth-abundant catalysts for water splitting. This work shows the design and properties of chiral CuO@Ni with three dimensional continuous macroporous framework. The chiral CuO@Ni exhibited lower OER overpotential and larger current density than many CuO-based catalysts. Its high catalytic activity for water splitting reaction is attributed to the CISS effect of chiral CuO, the large reactive area of its 3D porous structure, and the synergistic interaction between the chiral CuO and the Ni foam. Image 1 • Chiral CuO@Ni with three dimensional continuous macroporous framework. • Low OER overpotential (110 mV) to achieve 10 mA/cm2 current density. • Easy and effective way to enhance the activity of chiral earth-abundant catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Arc nanosynthesis of graphite-coated magnetic core-Au satellite nanoassembly. • Tailorable nanostructure and tunable surface functionalization of FeAu@G. • Different formation mechanisms of shells over cores and satellites enable FeAu@G. • Excellent negative linearity of Cr(VI) removal time with [Au wt.%]/[Au diameter]3. • Excellent negative linearity of K values to the diameter of Au satellites. Most magnetoplasmonic nanoassemblies with tunable geometries are commonly fabricated by the wet assembly approach, which is greatly restricted by the high complexity and severe conditions. This study applied a facile one-step arc discharge to fabricate graphite-encapsulated magnetic core-gold satellite (FeAu@G) nanoassembly with tailorable morphologies (35.5–58.8 nm of magnetic cores with 4.91- 0.335 nm of shells, and 4.63–9.01 nm of Au satellites with 1–4 graphite layers of shells) and tunable surface functionalization (hydrophobization, amination). The specific formation processes of graphite shells (i.e., dissolution-reprecipitation-graphitization for shells over magnetic cores, deposition-graphitization for shells over Au satellites) is essential to generate this unique nanoassembly. An storage-dependent consuming time for the removal of Cr(VI) by aminated FeAu@G presented an excellent negative linearity with [Au wt.%]/[Au satellite diameter]3. The reusability of aminated FeAu@G could be significantly aroused by the radio-frequency plasma treatment with an enhancement of 198–894 %. Hydrophobic FeAu@G could converse nitroaromatics recycled with an excellent negative linearity of catalytic activity values to the diameter of Au satellites. This work unlocks a versatile platform to design and produce magnetoplasmonic nanoassemblies with ideal complex nanostructures and surface functionality. [ABSTRACT FROM AUTHOR]

Interfacial charge separation is an essential issue to restrict catalytic activity of photocatalysts. In this work, we report a promising and easy-to-handle strategy to modulate the activity of a C 60 -based photocatalyst (C 60 @Pt) for visible-light-driven hydrogen evolution reaction (HER) with the coupling of magnetic substance that had weak ferromagnetism (Fe 3 O 4 microbeads as an instance). It is found that Fe 3 O 4 microbeads played a pivotal role in boosting photocatalytic activity and apparent quantum efficiency of C 60 @Pt for visible-light-driven HER, as the weak local magnetic field it induced around C 60 @Pt contributed to facilitating the separation of photo electrons from electron-donor in reaction system. This work shows a promising strategy to enhance photocatalytic activity of C 60 -based photocatalyst (C 60 @Pt as an instance) for visible-light-driven hydrogen evolution by coupling it with magnetic substance Fe 3 O 4 microbeads that had weak ferromagnetism. It is found that the Fe 3 O 4 microbeads played a pivotal role in enhancing photocatalytic activity of C 60 @Pt as the weak local magnetic field it induced around C 60 @Pt contributed to promoting the separation of photo-excited electrons from electron-donor. This strategy effectively boosted hydrogen evolution rate and AQE of C 60 @Pt. [Display omitted] • Modulate activity of C 60 -based photocatalyst via connecting weak magnetic substance. • Promote separation of photo-excited electrons by inducing weak local magnetic field. • AQE was boosted up to 2.5 times with the coupling of weak magnetic substance. • Hydrogen evolution improved up to 3.7 times when connecting weak magnetic substance. • Remarkably improve HER photocatalytic robustness of C 60 -based photocatalyst. [ABSTRACT FROM AUTHOR]