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Stability and antipoisoning effects are the main challenges for the application of commercial Pt/C catalysts. Herein, we soaked and adsorbed polydopamine to coat Pt particles on commercial Pt/C and subsequently converted the coatings to few-layer N-doped graphene by calcination to produce Pt/C@NC. The coatings effectively block the direct contact of Pt nanoparticles and electrolyte, thus enhancing the catalyst stability by avoiding Ostwald ripening and suppressing the competitive adsorption of toxicants, contributing to the enhancement of the antipoisoning ability. More importantly, the coatings do not hurt the oxygen reduction reaction (ORR) activity of commercial Pt/C, which exhibits a half wave potential of 0.84 V in an acidic electrolyte. The spectroscopic and theoretical results confirmed that the coatings originate from a strong Pt bonding to pyridinic N of N-doped graphene and that the high ORR activity results from the coordinately unsaturated carbon atoms, as the real ORR active sites, to strongly capture electrons from Pt.

The FLPs (Sn–OVs…Zn–OH) are in situ formed on ZnSn(OH)6 by using the electrochemical stability difference of Sn–OH and adjacent Zn–OH. Better electrons transport and stronger orbital interactions between FLPs and CO2 molecules on ZnSn(OH)6 realize the higher reaction dynamics.

Substantial overpotentials and insufficient and unstable active sites of oxygen evolution reaction (OER) electrocatalysts limit their efficiency and stability in OER-related energy conversion and storage technologies. Here, a template editing strategy is proposed to graft highly active catalytic species onto highly conductive rigid frameworks to tackle this challenge. As a successful attempt, two types of NiO

An industrial-scale time- and cost-effective route to produce a highly efficient and stable oxygen evolution reaction (OER) electrode is desirable and highly challenging. Here, we have developed a minute-scale Fenton-like reaction to produce a three-dimensional (3D) FeOOH/NiFe-LDH heterojunction OER electrode by using industrial Ni foam as an Ni source to react directly with a Fenton-like reagent. The resulting 3D electrode, comprising a xlow-crystalline nano-scale FeOOH/NiFe-LDH heterojunction with high electrolyte-permeability, afforded a remarkable OER performances with an overpotential of 238 mV at 100 mA cm−2, a Tafel slope of 28.9 mV dec−1, and stable running over 700 h. Our results suggested that the fully maximized three-dimensional FeOOH/NiFe-LDH heterojunction interactions would be the origination of the high OER activity, exhibiting big prospects for industrial-scale applications.

In this article, the roles of surface-active sites in dominating photoelectron selectivity for CO

Defects engineering of oxides plays a vital role in tuning their physicochemical and electronic properties and thereby determining their potential applications. However, the safe and controllable production of effective defects in the oxides is still challenging. Here, we report a facile one-pot solid lithiothermic reduction approach to generate graded oxygen defects in TiO2 nanoparticles. Various levels of lithium reduction are systematically studied, and meanwhile, a distinct phase transition from anatase TiO2 to cubic LixTiO2 is observed with the increasing lithium ratio. The structure and evolution of surface defects and bulk phase transition are investigated in detail. Afterward, we demonstrate their applications in carbon dioxide photoreduction and photothermal imaging. The slightly reduced TiO2 with effective oxygen defects affords a highly broadened solar spectrum absorption and yields significantly enhanced visible photocatalytic activity in CO2 conversion, which is further revealed by theoretical calculations. The highly reduced TiO2 with obvious phase transition shows enhanced solar absorption and achieves high photo-thermal-conversion efficacy, showing huge potential in photo-thermal-related applications. The lithiothermic reduction is a general and effective approach to produce defects and induce phase transition in oxides, which can be used in multiple applications.

The oxygen evolution reaction (OER) is a vital proton donor for various clean energy technologies. Here, we synthesized IrOx-decorated ultrathin NiFe-LDH nanosheets (thickness 1–2 nm) by a one-step co-precipitation method. The IrOx was uniformly dispersed on the surface of ultrathin NiFe-LDH nanosheets, greatly increasing the active sites and the electric conductivity for NiFe-LDH. As a result, the IrOx/U-NiFe-LDH exhibited excellent OER performance with a low overpotential (236 mV) and a Tafel slope (74.3 mA dec−1).

Developing a highly efficient and low-cost oxygen-evolution-reaction (OER) electrocatalyst is an important route to overcome the rate-determining step of water splitting. Here, we directly grew a CoS2 nanoarray core with an N-doped graphitic carbon (NGC) shell on Ni foam (NF) to construct a core–shell nanorod array electrode, CoS2@NGC@NF. The CoS2 core with a high work function (∼5.5 eV) tends to capture electrons from the NGC layer (4.5–5.2 eV) to induce an electron-poor NGC shell with a significant downshift of the carbon Fermi level, facilitating the adsorption of O-containing intermediates and affording decreased activation energy during the OER process. As a result, the three-dimensional NGC encapsulated CoS2 array assembly exhibited excellent electrocatalytic OER activity with a low overpotential of 243 mV at a current density of 10 mA cm−2 and a small Tafel slope of 71 mV dec−1 in 1.0 M KOH. Our findings may suggest that manipulating the interface energetics by the work function difference is a potential route to the design of high-performance OER electrocatalysts.

Efficiency of solar-driven CO2 into fuels is largely limited by the sluggish reaction kinetics resulting from high activation barriers and poor electron-hole separation. Here, a synergistic strategy was proposed to overcome these obstacles. As a prototype, KOH-modified Ni/LaTiO2N photocatalyst afforded a high performance in CO2 reduction with a generation rate of 9.69 μmol g−1 for CH4 and 0.31 μmol g−1 for CO, about 5 times higher than the catalytic activities of LaTiO2N. The prominent enhancement results in the following effects: (1) Schottky barrier at Ni/LaTiO2N interface boosts separation of electron-hole pairs. (2) The OH- of KOH as basic sites favors activation of CO2 into CO32- species, significantly improving the reaction kinetics of CO2 reduction. (3) The OH- also functions as hole acceptor, boosting the proton release from H2O oxidation.

The oxygen evolution reaction (OER) is a vital proton donor for various clean energy technologies. Here, we synthesized IrOx-decorated ultrathin NiFe-LDH nanosheets (thickness 1-2 nm) by a one-step co-precipitation method. The IrOx was uniformly dispersed on the surface of ultrathin NiFe-LDH nanosheets, greatly increasing the active sites and the electric conductivity for NiFe-LDH. As a result, the IrOx/U-NiFe-LDH exhibited excellent OER performance with a low overpotential (236 mV) and a Tafel slope (74.3 mA dec-1).

Wedge-shaped Ta3N5 nanoflakes with ultrathin top ends and preferentially exposed {010} facets were directly grown on a Ta plate via one-step nitridation. The mixed CsI–Cs2CO3 flux controls the growth kinetics of Ta3N5 and possibly has an impact on the dissolving process of Ta.

Tantalum nitride (Ta3N5) with an appealing band gap (∼2.1 eV) has emerged as a promising catalyst in the photocatalysis field. However, Ta3N5 application in the photocatalytic hydrogen evolution reaction (HER) is limited due to disadvantages such as unsatisfactory separation and transfer of photogenerated carriers. Here we utilize MoS2 as co-catalysts to promote the kinetics of photocatalytic H2 evolution over Ta3N5. The Ta3N5 nanorods were encapsulated into 3D hydrangea-like MoS2 for maximizing the contact areas between Ta3N5 and MoS2 and offering rich active sites. More importantly, spectroscopic analysis and theoretical calculations consistently reveal that the unique interfacial interaction, as well as the matching band alignment between Ta3N5 and MoS2, accelerates the photogenerated charge extraction from Ta3N5 to MoS2, reducing charge recombination losses in Ta3N5. Thus, the optimized Ta3N5/MoS2 hybrid exhibits a substantially enhanced hydrogen evolution rate (56.5 μmol h-1), over 22 times higher than that of pristine Ta3N5. This work may provide a general strategy to overcome the low photocatalytic activity of nitrides for hydrogen evolution.

We chemically deposited amorphous Ni(OH)2 layers over TaON particles with irregular surface morphology, and subsequently in situ reduced them to Ni (10-20 nm) nanoparticles, to construct a TaON@Ni photocatalyst. Such a hierarchical hybrid aims to combine the enhanced light absorption by the metal Ni plasmonic effect with accelerated charge separation by a Schottky barrier, and herein, achieves a higher photocatalytic activity in CO2 reduction than TaON.

CO2 activation is a vital knot for CO2-mediated energy conversion and storage. Frustrated Lewis pairs (FLPs) are well confirmed to be highly efficient in CO2 activation. Here, we synthesized the single-crystal ZnSn(OH)6 cube with exposed (100) facet (Sc) and ZnSn(OH)6 octahedra with exposed (111) facet (So) and created FLPs with different acid-base distance on these exposed facets by vacuum irradiation, resulting from the light unstability of terminal hydroxyls. Our results demonstrated that the FLPs with short acid-base distance on So are more efficient activation centers due to the strong orbital interactions, well exemplifying that shortening the Lewis acid-base distance is a potential route to develop highly efficient FLPs catalysts. In addition, as an initial attempt, the combination effects between facet junction separating charges and FLPs activating molecules were proposed to accelerate CO2 reduction. Our findings may provide new insights into designing photocatalysts with highly catalytic performances.

In this article, the roles of surface-active sites in dominating photoelectron selectivity for CO2 reduction products are well demonstrated over photocatalyst models of SrTiO3 {100} and {110} facets. On the easily exposed {100} facets terminated with Sr-O atoms, photoelectrons are of 8 mol % for CH4 and 92 mol % for CO generation. The Sr-O-Ti configuration in the {110} facets could enrich the surface charge density due to the lower interface resistance for higher photocatalytic efficiency (1.6 fold). The dual sites of Ti and adjacent Sr atoms are active for strong adsorption and activation of the generated CO* species from primary CO2 reduction on the surface, thus kinetically favoring the activity of photoelectrons (73 mol %) in hydrogenation for CH2* species and hence CH4 product. Inversely, the poor CH4 selectivity is due to difficulty in the subsequent photoelectron reduction reaction by the weak adsorption of CO* at the single-Sr site on the {100} facets, independent of the electron and proton concentration. Our results may offer some illuminating insights into the design of a highly efficient photocatalyst for selective CO2 reduction.

Tantalum nitride (Ta

Identifying the spatial effects of cobalt cations in cobalt-based heterogeneous catalysts contributes to develop effective peroxymonosulfate (PMS) activators in water treatment. Herein, we investigated typical tetrahedral and octahedral cobalt ions in CoAl2O4 and ZnCo2O4 via an inactive cation substitution strategy towards spinel Co3O4. ZnCo2O4 (0.095 min−1) performs remarkably better than CoAl2O4 (0.007 min−1) for degrading rhodamine B, while non-radical 1O2 is the dominant reactive oxygen species. Then, interface kinetics characterized by systemic electrochemical techniques indicate the feasibility of Co2+/Co3+ transformation and charge transfer resistance at catalyst-electrolyte interface determine intrinsic activity. Octahedral cobalt species exhibit superior intrinsic activities comparing with tetrahedral ones on the removal of several dye and aromatic pollutants. Additionally, flat band potentials of cobalt-based oxides reflecting Fermi level positions is a thermodynamic factor to activate PMS. Our work attempts to further understand spatial occupation-activity relationship of cobalt sites to design efficient PMS activators.

To break challenges in creating frustrated Lewis pairs (FLPs) on highly stable inorganic materials, an ordering FLPs route is proposed by irradiation of dual-metal hydroxide with alternating light-stable and light-unstable terminal hydroxyls on dual-metal hydroxide. As a successful example, a single-crystal ZnSn(OH)6 cube with a (100) surface of alternating Zn−OH and Sn−OH terminal hydroxyl groups is irradiated under 300 W Xe lamp to create oxygen vacancies (OVs, Lewis acid) via holes oxidizing light-unstable terminal hydroxyls at Sn sites. The FLPs are accordingly constructed between the photo-induced OVs and its proximal light-stable Zn−OH terminal hydroxyls (Lewis base), significantly contributing to the decreased barriers during capture, activation, and reduction of CO2 into CO with the assistance of H2. The present findings are a big leap for designing highly stable FLPs-based inorganic solid catalysts.

This paper proposes the Decision feedbackfeedforward per-survivor processing (DFF-PSP) iterative separation algorithm and the Monte Carlo integrationbased method to compute the theoretical bound for Paired carrier multiple access (PCMA) Single channel blind separation (SCBS) which is highly complex with long memory. The truncated PSP is employed while the pre- and post- cursors are disregarded to control the complexity. The delayed decisions feedforward and local decisions feedback filters are designed to process the pre- and post- cursors. The Bit-interleaved code modulation iterative decoder (BICM-ID) is combined with the second soft decision of the truncated PSP to obtain a better performance. The mixture signal model is regarded as a Multiple-access channel (MAC) with memory, and the theoretical performance bound is obtained via entropy inequality, Monte Carlo integration and Fano inequality. Simulation results show that the DFF-PSP iterative separation provides the good tradeoff between complexity and performance.

Depletion region at solid-solid or solid-liquid interface is mainly responsible for separating charge. Extending depletion region is an effective strategy to promote charge separation, and thus improving photoelectrochemical (PEC) performance. Herein, we designed an array heterojunction photoanode consisting of a-axis oriented-growth Ta3N5 nanorod arrays coated by SrTaO2N shell. This array heterojunction with a contiguous Ta3N5/SrTaO2N solid-solid and SrTaO2N/electrolyte solid-liquid junctions maximizes the charge separation and light absorption in depletion layer, shortens the hole diffusion distance to electrolyte, and effectively transfers electrons along the a-axis (light electron effective mass) of Ta3N5 to conductive substrate. As a result, compared with Ta3N5, Ta3N5/SrTaO2N array heterojunction exhibits more excellent PEC performance. Our results demonstrated a potential crystal oriented growth strategy of nanostructured heterojunctions with extended depletion region for promoting charge separation and overcoming the short carrier diffusion distance.

Nanoparticles are expected to improve properties of foaming agents and that prefabricated foams, further the performances of foamed concrete. In this study, foaming agents were prepared by introducing a certain content of nano-SiO2 (NS) and graphene (G), respectively. Effect of nanoparticles on foaming agent and that prefabricated foams has been investigated. Stability of prefabricated foams could be improved with the addition of NS, which might be attributed to the increased viscosity and a few changes in surface tension of foaming agents with NS. However, stability of the prefabricated foams would be degraded with the addition of G due to the obvious increase in surface tension of foaming agent with G. Furthermore, prefabricated foams through foaming agents with nanoparticles were used to prepare foamed concrete at dry density level of 500 kg/m3. Foamed concretes with decreased and evenly distributed pore sizes were obtained when foaming agents with NS were used, which is related to the much higher stability of prefabricated foams. Proper content of nanoparticles in foaming agents and the prefabricated foams can improve the mechanical properties of as-prepared foamed concrete. However, improvements for other performance of foamed concrete, such as thermal conductivity, water absorption and shrinkage, were not obvious when foaming agent with nanoparticles were used.