Electrocatalytic semihydrogenation of alkynols presents a sustainable alternative to conventional thermal methodologies for the high-value production of alkenols. The design of efficient catalysts with superior catalytic and energy efficiency for semihydrogenation poses a significant challenge. Here, we present the application of an electron-divergent Cu3Pd alloy-based heterojunction in promoting the electrocatalytic semihydrogenation of alkynols to alkenols using water as the proton source. The tunable electron divergence of Cu delta- and Pd delta+, modulated by rectifying contact with nitrogen-rich carbons, enables the concerted binding of active H species from the Volmer step of water dissociation and the C equivalent to C bond of alkynols on Pd delta+ sites. Simultaneously, the pronounced electron divergence of Cu3Pd facilitates the universal adsorption of OH species from the Volmer step and alkynols on the Cu delta- sites. The electron-divergent dual-center substantially boosts water dissociation and inhibition of completing hydrogen evolution to give a turnover frequency of 2412 h(-1), outperforming the reported electrocatalysts' value of 7.3. Moreover, the continuous production of alkenols at industrial-related current density (-200 mA cm(-2)) over the efficient and durable Cu3Pd-based electrolyzer could achieve a cathodic energy efficiency of 45 mol kW center dot h(-1), 1.7 times the bench-marked reactors, promising great potential for sustainable industrial synthesis.

The mass production of urea, the most widely used agricultural fertilizer, usually relies on energy- and carbon-intensive processes. The light-driven synthesis path has great potential for more sustainable techniques to produce urea from abundant naturally occurring resources, but this method suffers from the use of pure CO 2 and high-energy-driven forces (high temperature or ultraviolet light). Herein, we present a mild photocatalytic pathway for urea production from diverse nitrogenous species (such as NO 3 - , NH 3 , and N 2 ) and diluted CO 2 using visible light. We designed a palladium (Pd)-doped Schottky heterojunction, composed of graphene and titanium dioxide, as an effective photocatalyst to achieve on-farm urea generation. With the injection of visible-lightgenerated hot electrons from graphene to TiO 2 , the as-integrated Pd(I) centers with a special oxidation state of +1.36 in the TiO 2 lattice can initiate the universal reaction path of cascade reduction of NO 3 - /N 2 to NH 3 and resulting C-N coupling of CO 2 with as-formed or added NH 3 to transform diverse nitrogenous species and CO 2 into urea. The urea yield over the at.-Pd@TiO 2 /Gr photocatalyst is 1.62 mmol g -1 h -1 under visible-light irradiation with an apparent quantum yield of 1.05% at 400 nm and 0.39% even at 700 nm.

Electrocatalytic oxygenation of hydrocarbons with high selectivity has attracted much attention for its advantages in the sustainable and controllable production of oxygenated compounds with reduced greenhouse gas emissions. Especially when utilizing water as an oxygen source, by constructing a water-to-oxygenates conversion system at the anode, the environment and/or energy costs of producing oxygenated compounds and hydrogen energy can be significantly reduced. There is a broad consensus that the generation and transformation of oxygen species are among the decisive factors determining the overall efficiency of oxygenation reactions. Thus, it is necessary to elucidate the oxygen transfer process to suggest more efficient strategies for electrocatalytic oxygenation. Herein, we introduce oxygen transfer routes through redox-mediated pathways or direct oxygen transfer methods. Especially for the scarcely investigated direct oxygen transfer at the anode, we aim to detail the strategies of catalyst design targeting the efficient oxygen transfer process including activation of organic substrate, generation/adsorption of oxygen species, and transformation of oxygen species for oxygenated compounds. Based on these examples, the significance of balancing the generation and transformation of oxygen species, tuning the states of organic substrates and intermediates, and accelerating electron transfer for organic activation for direct oxygen transfer has been elucidated. Moreover, greener organic synthesis routes through heteroatom transfer and molecular fragment transfer are anticipated beyond oxygen transfer.

Nonoxidative dehydrogenation of propane is useful for the high selectivity to propylene but is suffering from the heavy coke deposition on the catalyst surface. Herein, we present a proof-of-concept application of a hole-hydrogen (H) couple on a metallic cobalt surface to decrease the deactivation rate. The coupled H atoms on the Cobalt (Co) surface, partially resulting from propane dehydrogenation, enabled the desorption of propylene to avoid deep hydrogenolysis and coke deposition and realize selective and durable propylene production, while conventional Co metal-based catalysts do not generate propylene. The optimized hole-H coupled Co catalyst provided a low deactivation rate (0.0036 h −1 ) and a high turnover frequency (55.6 h −1 ) for propylene production with a high propane flux (48 vol.% C 3 H 8 in gas feeds) at 550 °C.

Semihydrogenation of alkynes is a crucial industrial process for the mass production of polymer-grade alkenes and fine chemicals. An electrocatalytic semihydrogenation strategy presents a mild but powerful alternative to conventional processes under critical conditions and yet is suffering from a low catalytic efficiency due to the sacrificed intrinsic activity to depress unwanted overhydrogenation. Here, we report a negatively charged Pt (Pt delta-) induced by coupling with strong electron donator W2C nanoparticles in dual-junction materials to promote the electrocatalytic semihydrogenation of alkynes to alkenes using water as the hydrogen source. The negatively charged surface of Pt metals enables the polarization and unexpected preferential enrichment of alkynes, accelerating the following semihydrogenation process on the real Pt delta--based electrode. A significantly elevated energy barrier of overhydrogenation from the Pt delta- surface further ensures the semihydrogenation selectivity, breaking the selectivity-activity trade-off for semihydrogenation of a wide scope of alkynes. Moreover, the negatively charged Pt-based electrode as a reusable cathode could exhibit a turnover frequency of 310 h(-1) at -0.4 V versus Ag/AgCl, surpassing 6-fold the reported semihydrogenation catalysts with potential advantages for practical applications.

Selective electrocatalytic transformation of alcohols to aldehydes offers an efficient and environmentally friendly platform for the simultaneous production of fine chemicals and pure hydrogen gas. However, traditional alcohol oxidation reactions (AORs) in aqueous electrolyte unavoidably face competitive reactions (e.g., water oxidation and overoxidations reactions) for the presence of active oxygen species from water oxidation, causing an unwanted decrease in final efficiency and selectivity. Here, we developed an integrated all-solid proton generator-transfer electrolyzer to trigger the pure alcohol splitting reaction (ASR). In this splitting process, only O-H and C-H bonds can be cleaved at the proton generator (Pt nanoparticles), thereby completely avoiding all competitive reactions involving oxygen active species to give a > 99% selectivity to aldehydes. The as-generated protons are transported to the cathode by a three-dimensional (3D) conducting network (assemblies of ionomers and carbon spheres) for efficient hydrogen production. Unlike the poor selectivity (<22%) and durability (<3 h) of a conventional AOR electrolyzer, this ASR electrolyzer could be continuously operated at a low cell voltage of 1.2 V for at least 10 days to give a high Faradaic efficiency of 80-93% for aldehyde production.

As mainstream catalysts for phenol hydrogenation with good reusability and high selectivity under mild conditions, Pt- and Pd-based heterogeneous catalysts suffer from unsatisfied catalyst costs. The structures of metals (i.e., particle sizes, alloy structures, and porosity) and the acidity of the support were optimized to boost the intrinsic activity of noble metal nanocatalysts with a maximum promoting factor of 3.3. There is considerable scope for exploring more powerful methods for boosting the mass activity of metal catalysts. Herein, we demonstrate a novel size-dependent electronic interface effect in the heterojunctions of Pd nanocubes and sulfur-doped carbon (SC) supports to enhance phenol hydrogenation activity. Theoretical calculations and experimental results indicate that the size-dependent electron deficiency of Pd nanocubes on the designed SCs as electron acceptors results in an unexpected and universal promotion of phenol hydrogenation activity, outperforming free-standing Pd nanocubes by a factor of 9–19.

Dissociation of active H species over the catalytic sites with the carbon-supported Pt metals as the mainstream catalysts is crucial to facilitate hydrogen donation and accelerate the hydrogen addition process in catalytic hydrogenation systems to produce polymers, pharmaceuticals, agrochemicals, fragrances, and biofuels at million-ton scale. Much attention has been paid to the design of the more active catalytic site to effectively adsorb and activate reactants and H 2 molecules. At the same time, there is still a huge room to develop powerful strategies to accelerate the donation of acted H species to the reactants from the Pt surface further to boost the final catalytic efficiencies of Pt catalysts and depress the total Pt consumption. Herein, we present a new strategy for promoting the Pt-H bond dissociation by increasing surface hydrogen coverage on designed electron-deficient Pt nanoparticles. The electron deficiency of Pt nanoparticles has been successfully tuned by constructing a rectifying contact with an even “noble” boron-rich carbon support (Pt/BC). Theoretical and experimental results confirm the dominant role of the pronounced electron deficiencies of Pt nanoparticles in enhancing the H coverage for 2.3 times higher than that of neutral Pt nanoparticles, significantly boosting the Pt-H bond dissociation and thus the whole hydrogenation process as reflected by the extremely high turnover frequency (TOF) value of 388 h −1 at 30 °C and 10 bar H 2 for phenol hydrogenation on the Pt/BC, outperforming the bench-marked catalysts by a factor of 9.

Merging existing catalysts together as a cascade catalyst may achieve "one-pot" synthesis of complex but functional molecules by simplifying multistep reactions, which is the blueprint of sustainable chemistry with low pollutant emission and consumption of energy and materials only when the smooth mass exchange between different catalysts is ensured. Effective strategies to facilitate the mass exchange between different active centers, which may dominate the final activity of various cascade catalysts, have not been reached until now, even though charged interfaces due to work function driven electron exchange have been widely observed. Here, we successfully constructed mass (reactants and intermediates) exchange paths between Pd/N-doped carbon and MoC/N-doped carbon induced by interfacial electron exchange to trigger the mild and cascade methylation of amines using CO2 and H2. Theoretical and experimental results have demonstrated that the mass exchange between electron-rich MoC and electron-deficient Pd could prominently improve the production of N,N-dimethyl tertiary amine, which results in a remarkably high turnover frequency value under mild conditions, outperforming the state-of-the-art catalysts in the literature by a factor of 5.9.

Solar-driven production of hydrogen peroxide (H2 O2 ), as an important industrial chemical oxidant with an extensive range of applications, from oxygen reduction is a sustainable alternative to mainstream anthraquinone oxidation and direct hydrogenation of dioxygen methods. The efficiency of solar to hydrogen peroxide over semiconductor-based photocatalysts is still largely limited by the narrow light absorption to visible light. Here, the authors proposed and demonstrate the proof-of-concept application of light-generated hot electrons in a graphene/semiconductor (exemplified with widely used TiO2 ) dyad to largely extend visible light spectra up to 800 nm for efficient H2 O2 production. The well-designed graphene/semiconductor heterojunction has a rectifying interface with a zero barrier for the hot electron injection, largely boosting excited hot electrons with an average lifetime of ≈0.5 ps into charge carriers with a long fluorescent lifetime (4.0 ns) for subsequent H2 O2 production. The optimized dyadic photocatalyst can provide an H2 O2 yield of 0.67 mm g-1  h-1 under visible light irradiation (λ ≥ 400 nm), which is 20 times of the state-of-the-art noble-metal-free titanium oxide-based photocatalyst, and even achieves an H2 O2 yield of 0.14 mm g-1  h-1 upon photoexcitation by near-infrared-region light (≈800 nm).

Stable and portable ammonia (NH3) is a promising, low-cost, and environment-friendly medium for energy storage. How to achieve the rapid production of NH3 from reducing NOx- in aqueous systems and industrial wastewater via electrochemical methods remains the main challenge for practical application on a large scale. The corresponding electrocatalysts as the key materials in electrochemical devices suffer from low activity, especially in neutral systems. In this work, we successfully elevated the activity of the bench-mark Ru electrocatalysts to more than 30 times via construction of rectifying contact of Ru metals and noble carbons. We theoretically predicted and then rationally designed a new type of P-O rich carbon with large work functions as "noble" supports to attract a pronounced number of electrons from Ru metals at the rectifying interface. The resulting electron deficiency of Ru metals largely promotes the pre-adsorption and activation of NOx- anions, providing high Faradaic efficiencies (> 96%) and record-high turnover frequency values for universal NO2- and NO3- reduction in neutral solution.

Production of more than 20 million tons of epoxides per year from olefins suffers from low atom economy due to the use of oxidants and complex catalysts with unsatisfactory selectivity, leading to huge environmental and economic costs. We present a proof-of-concept application of electron-rich RuO2 nanocrystals to boost the highly selective epoxidation of cyclooctene via direct oxygen transfer from water as the sole oxygen source under mild conditions. The enhanced electron enrichment of RuO2 nanocrystals via the Schottky effect with nitrogen-doped carbons largely promotes the capture and activation of cyclooctene to give a high turnover frequency (260 h-1 ) of cyclooctene oxide, far surpassing the reported values (<20 h-1 ) of benchmarked catalysts at room temperature with oxidants. Our electron-rich RuO2 electrocatalysts enable efficient and durable hydrogen production (Faradaic efficiency >90 %) on the cathode without impacting on the selectivity to epoxide (>99 %) on the anode.

In this study, we have provided a facile solution to synthesize well-aligned titanium dioxide nanorods by using hydrothermal reaction. By calcining the materials under different atmospheres and temperatures, a batch of titanium dioxides with excellent oxygen evolution reaction(OER) catalytic efficiency were obtained. This new structured TiO2 photoanode material yields a high photocurrent density of 5.69 mA/cm(2) at 1.23 V vs. reversible hydrogen electrode(RHE) under simulated solar light(100 mW/cm(2)). Surface photovoltage techniques and other measurements were carried out to confirm that the enhanced photoelectrochemical performances were attributed to the synergistic effect of the phase junction and a certain content of surface states, which accelerate the separation and transmission of the photogenerated charges. This material with phase junction and surface states promises a potential application in the field of photoelectric catalysis under solar light.

Hydrogen peroxide (H2O2) is a clean disinfectant, bleaching agent, and value-added fuel in various systems and is industrially produced through multistep energy-intensive hydrogenation/oxidation using H-2 and O-2. The exploitation of metal-free catalysts for alternative H2O2 photoconversion is limited by their limited activity and selectivity, especially for the continuous H2O2 production using only air, water, and solar light. Now, a cheap and robust polymer, poly (4,4 ',4 ''-(1,3,5-triazine-2,4,6-triyl)triphenyl pyromellitimide) (PTTPI) was rationally synthesized by thermal structure-defect control under relatively low temperature (80-190 degrees C), and the resulting metal-free material with a concisely refined band structure functioned as an efficient and ultra-stable photocatalyst for H2O2 production over a wide pH range. The PTTPI photocatalyst with an optimized defective degree (0.51) and moderate bandgap (2.3 eV) exhibited a H2O2 production yield rate of 16.6 mu g h(-1) mg(cat)(-1) and a high apparent quantum efficiency of 16.2%. By merging the well-designed PTTPI catalyst with the water transport path of natural cotton, a zero-emission and sunlight-only input system is constructed for continuous H2O2 production from air and water in the natural environment. The design of the polyimide-based catalyst reveals a sustainable future toward efficient H2O2 synthesis with sunlight-only energy input, enabling its implementation in other photocatalytic systems and on-site processing communities.

Designing functional and reusable electrode materials to replace homogeneous versions of scarifying additives or mediators in electrochemical organic synthesis is of great importance for both the fundamental academics and practical production of various useful compounds. Herein, we rediscover the function of nitrogen-doped carbon monoliths (NxC) as de novo anode materials to trigger a new reaction path for the synthesis of acetals from the direct coupling of alcohols without the assistance of any mediator, oxidant, acid, or organic ligand. The lowered valence bands of carbon monoliths induced by doping nitrogen are of key importance for polarizing and activating the pre-adsorbed O-H groups of benzyl alcohol molecules to boost the high Faradaic efficiency (71% at 1.8 V versus Ag/AgCl) and reusability of NxC anodes, meeting the requirements of green chemistry.

Platinum (Pt) is the most effective bench-marked catalyst for producing renewable and clean hydrogen energy by electrochemical water splitting. There is demand for high HER catalytic activity to achieve efficient utilization and minimize the loading of Pt in catalysts. In this work, we significantly boost the HER mass activity of Pt nanoparticles in Pt-x/Co to 8.3 times higher than that of commercial Pt/C by using Co/NC heterojunctions as a heterogeneous version of electron donors. The highly coupled interfaces between Co/NC and Pt metal enrich the electron density of Pt nanoparticles to facilitate the adsorption of H+, the dissociation of Pt-H bonds and H-2 release, giving the lowest HER overpotential of 6.9 mV vs. RHE at 10 mA cm(-2) in acid among reported HER electrocatalysts. Given the easy scale-up synthesis due to the stabilization of ultrafine Pt nanoparticles by Co/NC solid ligands, Pt-x/Co can even be a promising substitute for commercial Pt/C for practical applications.

The activation of C–H bonds is a central challenge in organic chemistry and usually a key step for the retro-synthesis of functional natural products due to the high chemical stability of C–H bonds. Electrochemical methods are a powerful alternative for C–H activation, but this approach usually requires high overpotential and homogeneous mediators. Here, we design electron-deficient W 2 C nanocrystal-based electrodes to boost the heterogeneous activation of C–H bonds under mild conditions via an additive-free, purely heterogeneous electrocatalytic strategy. The electron density of W 2 C nanocrystals is tuned by constructing Schottky heterojunctions with nitrogen-doped carbon support to facilitate the preadsorption and activation of benzylic C–H bonds of ethylbenzene on the W 2 C surface, enabling a high turnover frequency (18.8 h −1 ) at a comparably low work potential (2 V versus SCE). The pronounced electron deficiency of the W 2 C nanocatalysts substantially facilitates the direct deprotonation process to ensure electrode durability without self-oxidation. The efficient oxidation process also boosts the balancing hydrogen production from as-formed protons on the cathode by a factor of 10 compared to an inert reference electrode. The whole process meets the requirements of atomic economy and electric energy utilization in terms of sustainable chemical synthesis.

Heterogeneous catalysts have been developed for C-C coupling reactions, but stand low activity and always proceed under harsh conditions. Photocatalytic Stille cross-coupling reaction as a green catalytic method for C-C bond formation is of great interest for a wide range of scientists but still lacks stable and highly efficient catalysts. Herein, we have designed an Au nanoparticle-graphitic carbon nitride heterojunction as an outstanding photo-catalyst for artificial photosynthesis in Stille cross-coupling reaction. The interface effect between metal and semiconductor makes electron rectify and prevents the recombination of electron-hole pairs. Moreover, the efficiency of Au nanoparticle catalysts could be adjusted by gold contents. Thus the turnover frequency(TOF) value reached the highest level of 788 h−1 over the optimal heterojunction catalyst. Most importantly, the C-C bond formation reaction has been proved to be carried out well under visible light irradiation, indicating the low-cost organic synthesis process. Further analysis confirmed the stability and general application of our heterogeneous Au nano-heterojunction catalyst.

Doping the host materials with either electron‐rich heteroatoms or electron‐deficient heteroatoms have been applied as a straightforward and main‐stream method to modify the electronic structures and boost the electrochemical activity for various reactions, including nitrogen reduction reactions (NRR). As the third type of dopants, isoelectric heteroatoms (exemplified with Si atoms in carbon framework in this work) have been designed as highly efficient active centers for NRR. As the same group element with a different size and electronegativity to carbon support, the isoelectric Si heteroatom (Iso‐e Si) creates localized singularities with a lone orbital that can act as an electron trap for pre‐adsorbed N2 molecules through coulomb interaction and thus facilitates the following activation process for NRR. Iso‐e Si atom thus functions as a special type of metal‐free single atom‐based electrocatalyst to largely boost the faradaic efficiency of pristine carbon support for NRR by a factor of 12, giving a remarkably high turnover frequency value of 0.52 h−1, comparable to atomically dispersed transition metal‐based electrocatalysts.