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Lithium-sulfur (Li-S) batteries are hampered by the infamous shuttle effect and slow redox kinetics, resulting in rapid capacity decay. Herein, a bifunctional catalysis CoB/BN@rGO with integrated structure and synergy effect between adsorption and catalysis is proposed to solve the above problems. The integrated CoB and BN are simultaneously and uniformly introduced on the rGO substrate through a one-step calcination strategy, applied to modify the cathode side of PP separator. The transition metal borides can catalyze the conversion of lithium polysulfides (Li2Sn, n ≥ 4), whereas the bond of B-S is too weak to absorb LPS. Thus BN introduced can effectively restrict the diffusion of polysulfides via strong chemisorption with LiSnLi+ ⋯N, while the rGO substrate ensures smooth electron transfer for redox reaction. Therefore, through the integrated adsorption/catalysis, the shuttle effect is suppressed, the kinetics of redox reaction is enhanced, and the capacity decay is reduced. Using CoB/BN@rGO modified PP separator, the Li-S batteries with high initial capacity (1450 mAh g−1 at 0.35 mA cm−2) and long-cycle stability (700 cycles at 1.74 mA cm−2 with a decay rate of 0.032% per cycle) are achieved. This work provides a novel insight for the preparation of bifunctional catalysis with integrated structure for long-life Li-S batteries.

The reasonable design of metal compound electrocatalysts is proved to be a good approach to accelerate the sluggish conversion kinetics of polysulfides for high performance lithium–sulfur (Li–S) batteries. Since metal cations usually serve as the active sites to interact with polysulfides, optimizing their electronic and valence states is vital to enhance catalytic activity, especially for electrochemical reactions involving multiple electrons. Herein, the electronic and valence states of metal active sites in hollow carbon-encapsulated Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7) nanospheres are modulated by introducing either donor defects (P dopants) or acceptor defects (Ni vacancies) via P-doping or NaBH4-etching, respectively. Such P dopants and Ni vacancies not only endow P-doped C/Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7-Pm) and NaBH4-etched C/Ni3ZnC0.7 (denoted as C/Ni3ZnC0.7-Bn) nanospheres with abundant defects and distortions, but also modulate the valence states of metal active sites in different ways. P dopants and accompanied Zn vacancies remarkably decrease the electron density of Zn active sites in C/Ni3ZnC0.7-P5 while the Ni vacancies contribute to the dramatic increase of Ni2+ species in C/Ni3ZnC0.7-B1 nanospheres. The modulated Zn sites could anchor polysulfides and serve as reservoirs to regulate the valence of Ni sites. However, the modulated Ni active sites with more Ni2+ species enable fast electron transfer between the Ni2+/Ni(0) pair and polysulfides, playing a more significant role in catalyzing the conversion of polysulfides. As a result, compared with C/Ni3ZnC0.7 and C/Ni3ZnC0.7-P5, C/Ni3ZnC0.7-B1 with more Ni2+ species exhibits stronger chemical adsorption ability toward polysulfides and catalytic ability to accelerate the conversion kinetics of polysulfides. When C/Ni3ZnC0.7-B1 nanospheres are used to modify commonly used PP separators for Li–S batteries, remarkable rate performance up to 4.0C (525.6 mA h g−1) and excellent cycling stability (a decay of 0.0179% over 1400 cycles at 1.0C) are achieved.

Hydrogen evolution reaction (HER) is one of the key components for the hydrogen-centered renewable clean energy system. Developing efficient HER electrocatalysts that make use of earth-abundant elements is highly desirable yet challenging. Herein, we report a three-dimensional (3-D) CoP3 nanoplate arrays in situ grown on carbon cloth (CoP3 NPAs/CC), which is synthesized by a facile topotactic phosphidation method under hydrothermal condition. As a HER electrocatalyst, the as-prepared CoP3 NPAs/CC exhibit great catalytic activity that is comparable to Pt, over a large pH range of 0–14. At pH = 0, such flexible and efficient CoP3 electrocatalysts can deliver a high current density of 100 mA cm−2 at an overpotential as low as 113 mV, with no apparent activity loss over 40 h. By theoretical calculation and experimental measurements, the outstanding HER performance of the CoP3 NPAs/CC can be attributed to the good conductivity property, synergistic effect between Co and P, unique rich-phosphorous CoP3 nanoplate arrays structure and the great intrinsic catalytic activity. As a highly efficient HER catalyst, CoP3 NPA offers a promising alternative of non-PGM catalysts for electrochemical hydrogen production.

Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction (HER) since it can adjust the electronic structure, active site, and phase. The reported studies mainly focus on designing P doped CoS2, while other phases of cobalt sulfide, such as Co1−xS and Co9S8 doped with P are rarely investigated for HER electrocatalysts. Herein, various cobalt sulfides (including CoS2/Co1−xS, Co1−xS, and Co9S8) doped with P are anchored on carbon cloth through a facile hydrothermal method. Among tested electrocatalysts, P doped Co1−xS exhibits excellent electrocatalytic performance with an overpotential of 110 and 165 mV (vs. RHE) for current densities of 10 and 100 mA·cm−2, respectively. Density functional theory calculations reveal that P doped Co1−xS possesses a smaller bandgap and more optimal hydrogen adsorption sites than pristine Co1−xS. This work initially investigates various cobalt sulfides doped with P and further gets insight into the activity improvement mechanism of P doping, which could guide the design of earth-abundant HER electrocatalysts for the “hydrogen economy”.

Pursuing cost-effective water-splitting catalysts is still a significant scientific challenge to produce renewable fuels and chemicals from various renewable feedstocks. The construction of controllable binder-free nanostructures with self-standing holey and ultrathin nanosheets is one of the promising approaches. Herein, by employing a combination of the potentiodynamic mode of electrodeposition and low-temperature phosphidation, three-dimensional (3D) holey CoP ultrathin nanosheets are fabricated on a carbon cloth (PD-CoP UNSs/CC) as bifunctional catalysts. Electrochemical tests show that the PD-CoP UNSs/CC exhibits outstanding hydrogen evolution reaction performance at all pH values with overpotentials of 47, 90, and 51 mV to approach 10 mA cm-2 in acidic, neutral, and alkaline media, respectively. Meanwhile, only a low overpotential of 268 mV is required to drive 20 mA cm-2 for the oxygen evolution reaction in alkaline media. Cyclic voltammetry and impedance studies suggest the enhanced performance is mainly attributed to the unique 3D holey ultrathin nanosheets, which could increase the electrochemically active area, facilitate the release of gas bubbles from electrode surfaces, and improve effective electrolyte diffusion. This work suggests an efficient path to design and fabricate non-noble bifunctional electrocatalysts for water splitting at a large scale.

Highly efficient and low-cost electrocatalysts toward oxygen evolution reaction (OER) hold their promises in renewable energy technologies such as water splitting. Herein, we reported a fast electrodeposition of highly efficient NiFe alloy onto three-dimension nickel foam (NF). Benefiting from the hierarchical structure, NiFe/NF exhibits high OER efficiency with a low onset potential and a low overpotential (191 mV at 10 mA cm−2), which outperforms the commercial catalyst and most reported catalysts up-to-date. Also, it shows a remarkably low Tafel slope of 44.1 mV as well as a long-time stability that the potential increased less than 10 mV after 30000 s OER at 100 mA cm−2. NiFe/NF is expected to surpass the commercial catalyst to serve as a non-noble-metal-based electrocatalyst for OER practical application.

The cobalt oxides and manganese oxides have high-activity potential for catalytic oxidation of volatile organic compounds (VOCs), while the mesoporous hollow morphology is crucial to the mass transfer of reactant and product. Therefore, it is worth investigating the effect of manganese substitution in mesoporous hollow cobalt oxides on catalytic oxidation. Herein, a partially disordered spinel structure is formed by the Mn substitution in Co3O4 and the mesoporous hollow microsphere is improved in morphology homogeneity with the decrease of Co/Mn ratio in the range of 1.8–28.8. The 5Co1Mn (Mn-substituted Co3O4 with Co/Mn at 5.4) exhibits outstanding catalytic activity for toluene oxidation with 50% CO2 generation at 237 °C, which is 21 °C lower than Co3O4. Moreover, the 5Co1Mn displays satisfactory stability in reusability, lifetime, and water resistance. The small defective crystallite, mesoporous hollow morphology, and high specific surface area endow Mn-substituted Co3O4 with more surface chemical adsorbed oxygen, enhancing the catalytic oxidation of toluene. Theoretical calculation on (3 1 1) plane of Co3O4 reveals that Mn2+ or Mn3+ substitution increases the formation energy of oxygen vacancy and makes it difficult to adsorb gaseous oxygen on the defective surface. The interaction between Co and Mn impedes the improvement of toluene oxidation because the mobility of lattice oxygen, the surface distribution of Co3+, and the ratio of surface adsorbed oxygen to surface lattice oxygen are hindered by Mn substitution. The chemical adsorbed oxygen is more active than lattice oxygen in the oxidation of adsorbed intermediates (phenolate, benzoate species, etc.). The Langmuir-Hinshelwood mechanism dominates in the catalytic oxidation at 200–250 °C, while the catalytic oxidation follows both the Langmuir-Hinshelwood mechanism and Mars-van Krevelen mechanism above 250 °C. This work provides some enlightenment for exploring the role of surface oxygen species in VOCs oxidation and uncovering the interaction in binary spinel oxides.

MXenes with good conductivity and hydrophilicity are a new family of potential electrocatalysts (e.g., for hydrogen evolution). However, pristine MXenes usually show unsatisfactory catalytic activi...

High Bi-ratio ternary sulfides have been recently reported as superior thermoelectric materials. However, the synthesis of high Bi-ratio Cu-Bi-S nanocrystal remains a challenge. Reported here are the synthesis and characterization of three-phase Cu-Bi-S nanocrystals with the nominal chemical formulae of Cu1.57 Bi4.57 S8 , Cu2.93 Bi4.89 S9 and Cu3 BiS3 . The samples were prepared using a Bi2 S3 precursor by varying the amount and type of Cu2-x S (i. e. Cu2 S or Cu7.2 S4 ) reactants. TEM images reveal that two new samples crystalized having nanorod morphology with radii of approximately 50 nm and lengths of 200 nm. XPS results indicate that the valence states of Bi in both the two new phases are +3 with viable oxidation states for Cu. UV-Vis-NIR absorption spectroscopy reveals that narrow direct bandgaps are 1.12 and 1.27 eV for Cu1.57 Bi4.57 S8 and Cu2.93 Bi4.89 S9 , respectively. Besides, this method could also be applied to synthesize the Cu3 BiS3 phase with a new nanoplate morphology. The as-synthesized Cu-Bi-S samples show Cu/Bi ratio-dependent photoresponsive properties. This study not only reports the structure and bandgap of two ternary sulfides, which have only been discovered in the mineral previously, but also provides an efficient method for synthesizing Bi-rich ternary chalcogenide nanocrystals.

Exploring highly-efficient and low-cost non-noble metal electrocatalyst toward the hydrogen evolution reaction (HER) is highly desired for renewable energy system but remains challenging. In this work, three dimensional hierarchical porous cobalt poly-phosphide hollow spheres (CoP 3 HSs) were prepared by topotactic phosphidation of the cobalt-based precursor via vacuum encapsulation technique. As a porous HER cathode, the CoP 3 HSs delivers remarkable electrocatalytic performance over the wide pH range. It needs overpotentials of −69 mV and −118 mV with a small Tafel slope of 51 mV dec −1 to obtain current densities of 10 mA cm −2 and 50 mA cm −2 , respectively, and maintains its electrocatalytic performance over 30 h in acidic solution. In addition, CoP 3 also exhibit superior electrocatalytic performance and stability under neutral and alkaline conditions for the HER. Both experimental measurements and density functional theory (DFT) calculations are performed to explore the mechanism behind the excellent HER performance. The results of our study make the porous CoP 3 HSs as a promising electrocatalyst for practical applications toward energy conversion system and present a new way for designing and fabricating HER electrodes through high degree of phosphorization and nano-porous architecture.

Developing high-efficiency, low-cost and non-precious metal electrocatalysts for future renewable energy conversion systems is highly desired. In this work, self-supported three-dimensional porous CoP 3 nanospheres on carbon cloth (CoP 3 NSs/CC) are fabricated via topotactic phosphidation of Co 3 O 4 NSs/CC. The synthesized CoP 3 NSs/CC, as a novel non-precious-metal electrocatalyst with large specific surface area and high porosity, exhibits efficient bifunctional electrocatalytic performance in alkaline medium, with Tafel slopes of 66 mV dec −1 and 72 mV dec −1 , and a current density of 10 mA cm −2 at overpotentials of −121 and 291 mV for HER and OER, respectively, which are remarkably superior to those of transition metal phosphides (TMPs). In addition, it just needs a cell voltage of 1.54 V to acquire a current density of 10 mA cm −2 for overall water splitting. The results of our work may shed light on the direction toward highly efficient bifunctional TMPs electrocatalysts with high phosphorous component.

Herein, porous WP 2 nanosheet arrays integrated on graphite paper (P-WP 2 NSs/GP) as 3D flexible cathode for electrocatalytic hydrogen evolution reaction (HER) are prepared by in situ phosphidation via vacuum encapsulation assisted by pulsed laser deposition technique. Compared to the electrode without pre-deposition process, the enhanced catalytic activities are attributed to the increased effective catalyst loading and the reinforced charge transport kinetics. The results make the present P-WP 2 NSs/GP as a promising cathode for energy conversion and paves a new way for designing and fabricating efficient electrodes toward HER.

The design and development of high-efficiency and non-noble-metal hydrogen evolution reaction (HER) electrocatalysts for future clean and renewable energy system has excited significant research interests over the recent years. In this communication, the polymorphic tungsten diphosphide (p-WP 2 ) nanoparticles with mixed monoclinic (α-) and orthorhombic (β-) phases are synthesized by phase-controlled phosphidation route via vacuum capsulation and explored as a novel efficient electrocatalyst towards HER. The p-WP 2 catalyst delivers superior performance with excellent stability under both acidic and alkaline conditions over its single phases of α-WP 2 and β-WP 2 . This finding demonstrates that a highly efficient hybrid electrocatalyst can be achieved via precise composition controlling and may open up exciting opportunities for their practical applications toward energy conversion.

Developing low-cost and highly-efficient non-precious metal bifunctional electrocatalysts towards the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an attractively alternative strategy to solve the environmental pollution problems and energy demands. In this study, metal–organic framework (MOF) derived porous cobalt poly-phosphide (CoP3) concave polyhedrons are prepared and explored as superior bifunctional electrocatalysts for the HER and OER. The prepared MOF derived CoP3 concave polyhedrons show excellent electrocatalytic activity and stability towards the HER and OER in both acidic and alkaline media, with the Tafel slopes of 53 mV dec−1 and 76 mV dec−1 and a current density of 10 mA cm−2 at the overpotentials of −78 and 343 mV for the HER and OER, respectively, which are remarkably superior to those of the transition metal phosphides (TMPs) and comparable to those of the commercial precious metal catalysts. In addition, they also offer efficient catalytic activities and durabilities under neutral and basic conditions for the HER. The results of our study may shed light on the direction towards highly efficient bifunctional TMP electrocatalysts with high phosphorous component.

The distinguishable physicochemical properties of MXenes render them attractive in electrochemical energy storage. However, the strong tendency to self-restack owing to the van der Waals interactions between the MXene layers incurs a massive decrease in surface area and blocking of ions transfer and electrolytes penetration. Here, in situ generated Ti3 C2 Tx MXene-carbon nanotubes (Ti3 C2 Tx -CNTs) hybrids are reported via low-temperature self-catalyzing growth of CNTs on Ti3 C2 Tx nanosheets without the addition of any catalyst precursors. With combined spectroscopic studies and theoretical calculation results, it is certified that the intralayered Ostwald ripening-induced Ti3 C2 Tx nanomesh structure contributes to the uniform precipitation of ultrafine metal Ti catalysts on Ti3 C2 Tx , thus giving rise to the in situ CNTs formation on the surface of Ti3 C2 Tx with high integrity. Taking advantages of intimate electrolyte penetration, unobstructed 3D Li+ /e transport, and rich electroactive sites, the Ti3 C2 Tx -CNTs hybrids are confirmed to be ideal 3D scaffolds for accommodating sulfur and regulating the polysulfides conversion for high-loaded lithium-sulfur batteries.

Transition metal phosphides (TMPs) are burgeoning as novel electrocatalysts to replace noble metals for electrochemical production of hydrogen. In this work, we propose a novel and cost-effective catalyst, molybdenum diphosphide (MoP2) three-dimensional porous structural nanoparticles with superior activity towards the hydrogen evolution reaction (HER). MoP2 nanoparticles catalyst exhibits an onset overpotential of −38 mV, a Tafel slope of 52 mV dev−1 and an exchange current density of 0.038 mA cm−2. Furthermore, the catalyst only needs low overpotentials of −121 and −193 mV to produce operationally relevant cathodic current densities of −10 and −100 mA cm−2, respectively, and its catalytic activity is maintained for at least 24 h. Comparative study with MoP nanoparticles as electrocatalyst for HER clearly indicates that MoP2 with high phosphor component can potentially improve the electrocatalytic activities. Density functional theory (DFT) calculation shows that the higher electrocatalytic activity of MoP2 over MoP can be attributed to a longer H P bond length, lower hydrogen adsorption energy, lower HER energy barrier and luxuriant surface active sites. This work may expand the TMPs family to poly-phosphides as active and cost-effective hydrogen electrode for the large-scale hydrogen production.

The development of high-efficiency and non-noble metal hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. In this work, monoclinic tungsten diphosphide (α-WP 2 ) and orthorhombic tungsten diphosphide (β-WP 2 ) particles were synthesized through a phase-controlled solid-state phosphating reaction route via vacuum encapsulation technique, and were evaluated as HER electrocatalysts. Structural characterizations indicate single phase highly crystalline α- and β-WP 2 particles with sub-micron sizes were successfully prepared. Both catalysts deliver remarkable catalytic activity for HER with good stability in acidic media. However, α-WP 2 particles exhibit better catalytic activity than β-WP 2 with a lower overpotential for achieving cathodic current density of 10 mA cm −2 and a smaller Tafel slope. Combining experimental measurements and theoretical calculations based on density functional theory (DFT), we conclude that the higher catalytic activity of α-WP 2 over β-WP 2 can be attributed to the less transfer of electron density from W to P due to a longer W-P bond length, the higher electron conductivity and better charge transfer, the lower kinetic energy barrier of H atom adsorption on catalysts surface for HER and longer H-P bond length for effective desorption of H atom to form H-H bond. Our findings may help the development of transition metal poly-phosphide with precise phase controlling technique for applications in hydrogen production.

Magnetic photocatalysts have attracted an increasing attention for photodegradation of organic containments and easy recycling. In this work, magnetic, single-crystalline Bi2Fe4O9 samples have been synthesized through a facile hydrothermal process and the morphologies were modulated by adjusting the Bi3+/Fe3+ precursor molar ratio and NaOH concentration. The most well crystalline Bi2Fe4O9 nanoplates were formed by self-assembled anisotropic growth along the (001) plane, with large exposed (001) surface. The Bi2Fe4O9 nanoplates exhibit excellent photocatalytic degradation of rhodamine b (RhB) under visible light irradiation with the assistant of a small amount of H2O2. The excellent photocatalytic performance of the Bi2Fe4O9 nanoplates was ascribed to the lower recombination rate of the photogenerated electrons and holes on the (001) surface, which was confirmed by detecting the hydroxyl radicals. In addition, Bi2Fe4O9 samples exhibit morphology-dependent magnetic properties. The mechanisms of morphology-dependent magnetic, photoadsorbing and photocatalytic properties of Bi2Fe4O9 crystals are discussed systematically. The magnetic Bi2Fe4O9 photocatalyst allows efficient utilization of solar energy and possible catalyst recovery via magnetically-enhanced gravity separation.

Bismuth oxyhalides (BiOX, X = Cl, Br, I) as effective photocatalysts have attracted a wide attention for its outstanding performance on air purification with solar energy. In this work, a series of band-gap engineered BiOClxBr1−x homogeneous solid solution materials were explored as efficient visible-light induced photocatalysts. The BiOClxBr1−x solid solution photocatalysts with 3D hierarchical nanostructures have been successfully synthesized through a facile temple free hydrothermal method. The prepared BiOClxBr1−x possess a single tetragonal crystal structure without any secondary phases in spite of x varying from 0 to 1 indicating a homogeneous solid-solution characteristic. However, the band gaps of BiOClxBr1−x solid solutions are modulated from 3.30 to 2.75 eV by decreasing x from 1 to 0, which extends the light absorption from 375 nm to 450 nm. The obtained BiOCl0.5Br0.5 sample displays enhanced photocatalytic activity for the oxidation of NO, with a good stability under visible light. The existence of hydroxyl radicals and super oxygen radicals confirm its photocatalytic activities. The highly enhanced visible light photocatalytic activity of BiOCl0.5Br0.5 can be ascribed to the large specific surface area, hierarchical structures and the modified band structures. Furthermore, the modified band-gap adapts the balance between adequate redox potentials and effective visible light absorption. The present work provides novel insights into the design and synthesis of 3D hierarchical nanostructures with band-gap engineering to explore novel photocatalysts.

Searching for inexpensive and earth-abundant photocatalysts with high activities has attracted considerable research in recent years. In this work, semimetallic tungsten diphosphide (WP2) micro-particles are explored as a novel photocatalyst for the first time. The WP2 particles were synthesized through a solid-state reaction route via vacuum encapsulation technique following by water washing. The first principle calculations and electric transport measurements show a semimetallic characteristic of WP2, however a strong absorption in the UV range is observed. The prepared WP2 particles exhibit an admirable photocatalytic activity towards oxidation of methyl orange and reduction of water for H2 evolution with the assistance of co-catalyst element Pt under UV light irradiation. Hydroxyl radicals detected by fluorescence spectroscopy in the solution in the presence of WP2 under UV light irradiation confirms the photoactivity. Furthermore, the photocatalyst shows a good photostability and reusability even after three successive experiment runs. Based on the experimental measurements and theoretical calculations, a possible photocatalytic mechanism is proposed for semimetallic WP2. The present study may provide a chance for practical applications of the semimetallic material WP2 in the field of photocatalysis.

The design and development of high-efficiency and non-noble metal hydrogen evolution reaction (HER) electrocatalysts with optimized nanostructures for human clean and sustainable energy systems has attracted significant research interest over the past years. Herein, self-supported semimetallic tungsten diphosphide nanowire arrays on carbon cloth (WP2 NWs/CC) were topotactically fabricated by in situ phosphidation of a WO3 NWs/CC precursor. Such a binder-free flexible HER cathode with integrated three-dimensional nanostructures can not only provide a large surface area to expose abundant active sites, but also facilitate electrolyte penetration for electrons and electrolyte ions. The WP2 NWs/CC electrode exhibits superior catalytic performance, and it needs overpotentials of 109 and 160 mV with a small Tafel slope of 56 mV dec−1 to achieve current densities of 10 and 50 mA cm−2, respectively. High stability in acidic media is also observed for the catalyst for a duration of 20 hours at least. In addition, density functional theory (DFT) calculations indicate a low kinetic energy barrier for H atom adsorption on the WP2 surface which guarantees the excellent catalytic activity of the catalyst, and the influences of phosphidation temperature on the HER activity are also studied. The excellent electrocatalytic activity makes the present 3D structured WP2 NWs/CC a promising catalyst for large scale highly pure hydrogen evolution by electrochemical water splitting.

Self-supported porous cobalt poly-phosphide nanoneedle arrays on carbon fiber paper (CoP3 NAs/CFP) are fabricated via topotactic phosphidation of the Co(OH)F/CFP precursor. The prepared CoP3 NAs/CFP, as a 3D structured electrocatalyst with a large specific surface area and high porosity, exhibits superior bifunctional electrocatalytic activity and durability for both the HER and OER.

A hybrid of graphene nanoribbons (GNRs) interlacing hollow NiCoO2 (G-HNCO) nanocages in a size range of 300~500 nm with rough surface is synthesized by a chemical etching Cu2O templates and followed by GNR interlacing process. The G-HNCO showed high electrochemical performance of oxygen evolution reaction (OER), which exhibited small onset potential of 1.50 V and achieved current densities of 10 mA cm−2 at potentials of 1.62 V. Also, the hybrid delivered high capacitance of 937.8 F g−1 at 1 A g−1 in supercapacitor (SC) tests as well as stable cycling performance in both OER and SC measurements. The approach to synthesize the hybrid is simple and scalable for other graphene nanoribbon-based electrocatalysts.