Background: Fabricating strong substrate-catalyst interaction is highly essential to boost the oxygen evolution reaction (OER). Methods: Herein, we report an electrochemical strategy for synthesizing nitrogen/phosphorus co-doped graphene (ENPG) using histidine and sodium phytate (SP) or phytic acid (PA) as precursors. The resulting ENPG features abundant nitrogen (e.g., pyridinic N) and phosphorus functional groups (PFGs, such as phosphonic acid (-PO(OH)(2)) and phosphate ester (-OPO(OH)(2)) moieties), enabling effective coordination with metal atoms. These functional groups synergistically optimize Co-N/O electronic structure and boost electron transfer kinetics, reducing eta by 104 mV (at 10 mA cm(-2)) for the Co-loaded ENPG (ENPG-Co) vs. pristine ENPG. Significant Findings: In-situ FTIR and Raman spectroscopy confirm that Co-N-C and Co-O moieties serve as primary active sites, significantly enhancing the OER activity. X-ray absorption fine structure (XAFS) results and theoretical calculations further reveal that PFGs provide distinct anchoring sites for Co atoms, thereby regulating its coordination environment. This work highlights an electrochemical strategy for heteroatomic doping of graphene and subsequent regulation of active-site coordination environments, resulting in exceptional OER performance.

The exploration of sustainable approaches for plastic waste disposal has emerged as an urgent imperative task. This research presents an innovative and eco-friendly electrochemical route to degrade plastic waste, ethylene glycol (EG), into value-added formate. To this end, an interesting hollow FeOOH/CoOOH heterostructure is successfully fabricated for EG oxidation. The difference in work functions between FeOOH and CoOOH results in the establishment of a built-in electric field (BEF), which is beneficial for the adsorption of EG and *OH. As a result, the FeOOH/CoOOH demonstrates outstanding catalytic performance in the EG oxidation reaction (EGOR) with an exceptionally low potential of only 1.32 V at 10 mA cm-2 and a high Faraday efficiency of 92.19 % for formate generation. Glycollic acid is identified as a pivotal intermediate in the EGOR by in-situ infrared spectroscopy. Theoretical computations disclose that the FeOOH/CoOOH heterostructure not only causes an upward shift of the d-band center but also largely enhances the *OH adsorption, thus speeding up the cleavage of the inert C-C bond and markedly facilitating the conversion of EG to formate. This research not only enriches the fundamental comprehension of the EGOR but also provides deep insights for the rational design of highly selective and active EGOR catalysts.

Fabricating strong substrate-catalyst interactions is essential for regulating the bond length of catalytic sites to boost catalytic performance, yet it remains challenging. Herein, we synthesized M, N, and S tri-doped graphene (M-N-S-GR) using sulfonated metal phthalocyanine (TSMPc, M = Cu, Fe, Co, Ni) as a precursor, enabling high loading of Pt nanoparticles (denoted Pt/M-N-S-GR, M = Cu, Fe, Co, Ni). The N and S co-doping synergically stabilize Pt nanoparticles on M-N-S-GR, achieving dendritic dispersion and maximizing active sites. Furthermore, engineering the Pt-C bond length optimizes of methanol oxidation reaction (MOR) on these Pt/M-N-S-GR catalysts, with performance following the order of Pt/Cu-N-S-GR > Pt/Ni-N-S-GR > Pt/Co-N-S-GR > Pt/Fe-N-S-GR. Correspondingly, Pt/Cu-N-S-GR exhibits the highest mass activity (2368 mg(Pt)(-1)), which is 5.78 times that of commercial Pt/C (410 mg(Pt)(-1)). Density functional theory (DFT) calculations reveal that adsorption energy and bond length at the active sites primarily determine the MOR activity on Pt/M-N-S-GR. This work provides an approach for the fabrication of highly active MOR catalysts via strengthening the substrate-catalyst interaction.

Although electrochemical synthesis serves as a green and cost-effective method to prepare hydroxyl- and carboxyl-rich functionalized graphene, the process encounters difficulties owing to the relatively low concentration of active species at the surface and interface. Here, we report a spatial confinement reaction for the electrochemical synthesis of functionalized graphene. Employing perchloric acid (intercalating agent) and ammonium hexafluorophosphate (co-reagent), we achieve controllable synthesis of hydroxyl-rich functionalized graphene, where systematic modulation of the perchloric acid concentration directly governed the resultant degree of functionalization. Furthermore, substituting formic acid for perchloric acid extends this method to prepare carboxyl-rich functionalized graphene, highlighting its adaptability for tailoring graphene surface chemistry. The hydroxyl groups impart the functionalized graphene high rejection rates against NaCl, KCl, MgCl2, and K2SO4 in water purification and desalination, while carboxyl groups significantly facilitate the functionalized graphene for both hydrogen evolution reaction and oxygen evolution reaction, as evidenced by electrochemical measurements and theoretical calculations. This work highlights the electrochemical functionalization of graphene achieved simultaneously during graphite electrolysis, with demonstrated applications in water desalination and water splitting.

Metal-organic frameworks (MOFs) and layered double hydroxides (LDHs) have emerged as highly efficient platforms for electrochemical sensors due to their simplicity, rapid response, low cost, and elevated sensitivity. However, the underlying mechanism of their interaction in electrochemical sensors is still unclear. Herein, the porous composite of MOF-supported LDHs (NiCu MOF@LDHs) is successfully fabricated using a simple hydrothermal method. Interestingly, the integration of LDHs and MOFs synergistically enhanced the hierarchical structure of the composite, leading to an increased specific surface area and improved electrical conductivity. Thus, the NiCu MOF@LDHs/GCE presents excellent glucose sensing features, including a good linear range (4.9504-1.1701 mM and 1.1701-2.8248 mM), a low detection limit (1.4249 mu M, S/N = 3). Specifically, the sensor exhibited enhanced sensitivities (1071.1 and 545.2 mu A mM-1 cm-2) and high selectivity in the presence of common interfering species including dopamine, hydrogen peroxide, ascorbic acid, L-arginine, and sodium chloride. Furthermore, the NiCu MOF@LDHs/GCE sensor demonstrated excellent performance in the practical detection of glucose levels in human serum, appreciating its potential for real-time applications. This work not only highlights the unique structural and functional properties of the NiCu MOF@LDHs composite but also paves the way for its future applications in glucose sensing and electrochemical biosensing.

Metal nanoclusters(MNCs)possess distinct chemical properties due to their diverse electronic structures.As a class of promising model catalysts,it is of importance to explore the relationship between their structures and properties.

Pt-based nanomaterials are considered to be the optimal electrocatalysts for hydrogen evolution reaction (HER), while its high cost and limited natural abundance pose significant barriers to large-scale application. Pt nanoclusters (Pt NCs) with high specific surface area and high atom utilization have promising catalysis application for efficient HER. Nonetheless, the pursuit of highly active and stable Pt NCs remains a challenge, as surface ligands may impede their functionality, whereas absence of surface ligand protection can result in instability. Herein, a series of Pt6 NCs with varying quantities of ligands were fabricated by annealing under 300 degrees C for different times. The results show that the removal of appropriate amount of ligands can enhance the catalytic activity and meanwhile preserve stability of Pt6 NCs. Notably, the optimized sample with annealing treatment for 2 h (Pt6/CNT-2) displayed a superior HER performance with an overpotential of only 24.6 mV at 10 mA center dot cm-2 and high stability, comparable to that of commercial Pt/C. Furthermore, the mass activity of Pt6/CNT-2 at -0.05 V is 19-fold greater than that of commercial Pt/C, significantly reducing the consumption of precious metals. This work provides a novel idea for designing ultrasmall noble-metal NCs electrocatalysts with excellent activity and stability.

Despite excellent charge-discharge performance in carbon-based supercapacitors, their mechanisms across pH solutions remain unclear due to difficulties decoupling capacitive effects from porous structures and intricate micro-nano molecular/ionic channels. To investigate these mechanisms, we electrochemically synthesize structure-defined, nanohole-free N-doped graphene (ENG) as a model system. Attenuated total reflection in situ infrared spectroscopy (ATR-FTIR) reveals splendid electrochemical activity for pyridinic N and carboxyl functional groups in acidic medium. In contrast, hydroxyl groups dominate the charge-discharge behavior of ENG in alkaline medium. This behavior differs from the neutral medium scenario, where only CO bonds produce detectable ATR-FTIR peaks. Theoretical calculations identified strong adsorption affinity of pyridinic N and carboxyl functional groups for H+ over OH-, which directly enhances the electrochemical activity of ENG in acidic medium. This work pioneers a targeted synthesis strategy for ENG, establishing it as a robust model to decode charge-discharge mechanisms of carbon-based materials across the full pH range.

The M-N-C (M = non-noble metal) materials have been utilized as highly active and cost-efficient catalysts for boosting the ponderous kinetics of oxygen reduction reaction (ORR). However, the fabrication and tailoring of bi-active sites in M-N-C catalysts are essential for ORR. In this investigation, the N-doped porous carbon supported Co- and Zn- based nanoparticles (Co/Zn-N-C) catalyst was synthesized by carbonizing the composite of ZIF-8 and cobalt phthalocyanine. By tailoring the numbers of active sites in Co/Zn-N-C, the catalyst achieved a maximum half-wave potential (E1/2) of 0.846 V (vs RHE) and a highest limiting current density of 5.4 mA cm-2 in alkaline medium. After 20,000 cyclic voltammetry cycles, the E1/2 shift of Co/Zn-N-C has been only shifted about 30 mV, outperforming commercial Pt/C catalysts (126 mV). Density Functional Theory calculations reveal that the cooperative interaction between adjacent Zn and Co active sites enhances the adsorption of ORR intermediates, thus boosting the overall reaction kinetics. This investigation offers a novel strategy for the construction of highly active and cost-effective metal catalysts as well as tailoring the numbers of active sites for ORR.

Despite the widespread application of the reconstructed transition metal phosphatesin promoting the ponderous kinetics of oxygen evolution reaction (OER), achieving profound reconstruction of ternary active sites remains essentially challenging, primarily due to the inherent difficulties in fabricating trimetallic pre-catalysts with typical compositions and morphologies. Herein, we display an electrochemical method for the deep reconstruction of ternary active sites in Co-based trimetallic phosphate nanoboxes (NiyFexCo2-x-yP2O7/C). The hollow cubic NiyFexCo2-x-yP2O7/C favors the accessibility of electrolytes, thus achieving deep reconstruction after the multi-cyclic voltammetry treatment (Re-NiyFexCo2-x-yP2O7/C). The generated low-crystalline MOOH (M=Ni/Fe/ Co) grants the Re-NiyFexCo2-x-yP2O7/C catalyst superior electrocatalytic ability for OER with an overpotential of 230 mV at 10 mA cm-2, a small Tafel slope of 58.5 mV dec-1, and outstanding stability, which outperforms those of Co-based mono/bimetallic catalysts and even commercial RuO2. The active sites in MOOH for boosting OER has been revealed by in situ Raman studies and theoretical calculations. This work provides a new approach for the construction of pre-catalysts of trimetallic phosphate and the subsequent reconstruction for highly efficient OER.

The practically low energy density limits the large-scale application of graphene in supercapacitors. Here, we propose a space-confined method for the preparation of fluorine-modified graphene (FG) by using fluorine-containing groups (PF6- or BF4-) as co-intercalated ions and reactants. The semi-ionic C-F bonds in FG contribute a brilliant capacitive performance in both acidic and alkaline electrolytes. Particularly, in alkaline medium, the FG electrode exhibited an ultrahigh specific capacitance (1210 F g-1), surpassing 2 orders of the theoretical capacitance value of graphene. Meanwhile, the FG-assembled symmetrical supercapacitor device (FG-SSD) possesses ultrahigh energy density (418.7 Wh kg-1) and power density (2 kW kg-1) in acidic medium, highlighting the practical application of supercapacitors. Theoretical calculations revealed an increased electrochemical double layer capacitance and amplified the electrochemical window of FG-SSD. This work demonstrates a spatially confined method for the preparation of functional graphene and its spectacular potential for supercapacitor-related electronics.

Chemical functionalization of graphene is a topic of paramount importance to broaden its applications in chemistry, physics, and biological science but remains a great challenge due to its low chemical activity and poor dispersion. Here, we report a strategy for the photosynergetic electrochemical functionalization of graphene (EFG). By using chloride ion (Cl-) as the intercalation anions and co-reactants, the electrogenerated radicals confined in the expanded graphite layers enable efficient radical addition reaction, thus grasping crystallineperfect EFG. We found that the ultraviolet irradiation and applied voltage have increased the surface/interface concentration of Cl', thus boosting the functionalization of graphene. Theoretical calculation and experimental results verified the oxygen evolution reaction (OER) on EFG has been improved by regulating the doping of chlorine atoms. In addition, the reduced interlayer distance and enhanced electrostatic repulsion near the basal plane endow the fabricated EFG-based membrane with high salt retention. This work highlights a method for the in situ functionalization of graphene and the subsequent applications in OER and water desalination.

Transition metal phosphates possess outstanding chemical and structural stability, high catalytic activity, excellent conductivity, and the ability to customize their morphology during synthesis. Despite these brilliant features, the utilization of these metal phosphates in electrochemical sensors, remains largely unexplored. In this study, we developed an innovative strategy to design corner-fractured copper phosphate micro-rods (CF-CP MRs), which were subsequently transformed into four-edged copper/cobalt phosphate microplates (FE-CCP MPs). Typically, controlled reaction conditions promote preferential growth of Cu2+ nuclei along specific crystallographic directions, resulting into novel rod-like shape, while fractured corners arise from specific crystal lattice arrangements, offering the boosted electrocatalytic performance. Subsequently, formation of FE-CCP MPs is attributed to the mixing of dissimilar crystal structures of copper and cobalt precursors, resulting in unique hetero-structure with sufficiently enhanced electrocatalytic activity. Moreover, the cyclic voltammetry (CV) was systematically investigated, shedding light on the efficiency of distinctive morphologies for uric acid (UA) electro-oxidation. Finally, the novel FE-CCP MPs hybrid material demonstrates appreciated sensing characteristics for UA detection, including high sensitivity (7.87 mu A mM(-1) cm(-2)), a wide linear detection range (20 nM similar to 357 mu M), and a low detection limit (12 nM, S/N = 3) in 0.1 M phosphate-buffered saline (PBS). Furthermore, the developed sensor was highly selective for UA detection, reproducible, and stable. Owe to its unique structural and chemical aspects, the prepared copper/cobalt phosphate architecture should find use in several electrochemistry related applications such electrocatalysis, energy storage and energy conversion. In addition, our designed strategy might be extended to synthesize other inorganic metal phosphates with unique structural features.

For large-scale hydrogen production from electrocatalysis of water, the Ni- and/or Fe-based catalysts were commonly used but limited by the ultrahigh overpotential and poor stability at high current density (>500...

We present a methodology for creating bi-active sites and co-doped M–N–C catalysts, showcasing potential applications in various energy-related fields.

The MNC (M = non-noble metal) materials have been utilized as highly active and cost-efficient catalysts for boosting the ponderous kinetics of oxygen reduction reaction (ORR). However, the fabrication and tailoring of bi-active sites in MNC catalysts are essential for ORR. In this investigation, the N-doped porous carbon supported Co– and Zn- based nanoparticles (Co/ZnNC) catalyst was synthesized by carbonizing the composite of ZIF-8 and cobalt phthalocyanine. By tailoring the numbers of active sites in Co/ZnNC, the catalyst achieved a maximum half-wave potential (E1/2) of 0.846 V (vs RHE) and a highest limiting current density of 5.4 mA cm−2 in alkaline medium. After 20,000 cyclic voltammetry cycles, the E1/2 shift of Co/ZnNC has been only shifted about 30 mV, outperforming commercial Pt/C catalysts (126 mV). Density Functional Theory calculations reveal that the cooperative interaction between adjacent Zn and Co active sites enhances the adsorption of ORR intermediates, thus boosting the overall reaction kinetics. This investigation offers a novel strategy for the construction of highly active and cost-effective metal catalysts as well as tailoring the numbers of active sites for ORR.

As model catalysts, it is necessary to study the relationship between the structure and properties of ultra-small metal nanoclusters (MNCs) and to reduce their steric hindrance as much as possible, e.g. preparing ultrasmall MNCs protected by ultra-short ligands. However, it is challenging to attain various MNCs with the same cores but different surface stabilizing ligands. Additionally, shortening the chains of protecting ligands will lead to larger MNC cores. Here, four different Pd NCs (Pd6(SC4H9)12, Pd6(SC8H17)12, Pd6(SC6(C2)H17)12 and Pd6(SC6H13)12) were successfully synthesized by a slow synthesis process. All these clusters consist of six Pd atoms and are stabilized by 12 thiols with different chain lengths and steric hindrance. The catalytic properties of the as-prepared Pd6 NCs were evaluated using the catalytic reduction of p-nitroaniline to p-phenylenediamine as a model reaction. The outcomes indicated that shortening the chain length of the protecting thiols could enhance the catalytic activity of the Pd6 NCs. Notably, stable and active ultra-small Pd6 clusters stabilized by ultra-short ligands (HSC4H9) were successfully synthesized. Although the performance of Pd6(SC4H9)12 clusters protected by the ultra-short thiols is lower than that of commercial palladium on carbon (Pd/C), they display higher stability. Interestingly, the activity of Pd6 NCs protected by ethyl-branched alkane thiols is also better than that of Pd6 NCs protected by the alkane thiol ligands with the same chain length or the same number of carbon numbers. This work provides clear evidence that the catalytic activity of atomically precise MNCs can be controlled by regulating the surface stabilizing ligands.

Rational design and fabrication of efficient catalysts for overall water splitting in an integrated electrolyzer are essential for energy storage and conversion. Herein, an ultra-small substitutional Zn-doped Ru/RuO2 heterostructure (5.6 nm) is synthesized through a facile pyrolyzing strategy as an efficient bi-functional electrocatalyst for water splitting in both acidic and alkaline media. Experiments demonstrate that introducing appropriate alien atoms into RuO2 with an amorphous state can effectively optimize the electron structure and expose abundant defects, and thus increasing the number of active sites and improving the intrinsic activity of RuO2 for the oxygen evolution reaction (OER). In addition, the high hydrogen adsorption capability of metallic Ru makes Ru-RuO2 heterointerface suitable for water splitting. Notably, the Ru/ZnRuO2 displays low overpotentials at 10 mA cm(-2) with only 184 mV for OER in 0.5 m H2SO4 and 35 mV for HER in 1.0 m KOH. Besides, the as-synthesized Ru/ZnRuO2 displays cell voltages of 1.540 and 1.567 V (at 10 mA cm(-2)) for water splitting with remarkable durability for more than 220 and 100 h, respectively, in acidic and alkaline media. This work provides a facile strategy for designing pH-universal electrocatalysts toward overall water splitting.

Electrochemical flow cells based on gas diffusion electrodes (GDEs) provide a potential means to achieve industrial-compatible massive CO production. However, the application of flow cells is hindered by the stability issue caused by GDE hydrophilizing and electrolyte flooding. The current strategies have certain limitations in maintaining the long-term hydrophobicity of GDE. Inspired by the superhydrophobic materials in nature, here a constructionally engineered superhydrophobic GDE is presented for boosting the stability of CO2 reduction to CO in flow cells under industrial-compatible current densities. This superhydrophobic GDE is comprised of micro/nano-structured CNTs/graphene composites with abundant and robust single-atomic Ni-N-x active sites (Ni-SA-CNT@G). The unique integrated hierarchical structure with highly exposed surface area and enhanced mass/charge transfer contributes to an industrial-scale CO partial current density of 406.5 mA cm(-2) with a FECO of 96.3% in a flow cell(.) Notably, the robust superhydrophobic micro/nanostructure efficiently resists electrolyte flooding over the GDE during the CO2RR, thus maintaining a stable three-phase interface. Over 70 h stability is demonstrated at an industrial-compatible current density of 300 mA cm(-2). These results open up new opportunities for industrial-level CO production via electrochemical CO2RR.