High-performance Energy Conversion Research Articles

Nitrogen-doped interpenetrating porous carbon/graphene networks for supercapacitor applications

We demonstrated a novel strategy to prepare nitrogen-doped interpenetrating porous carbon/graphene (NIPCG) networks based on interpenetrating poly(o-phenylenediamine)/N-doped graphene networks. The as-prepared NIPCG shows both high nitrogen content of 13.1 at.% and density of 1.13 g cm−3, and displays ultrahigh specific gravimetric and volumetric capacitances of 673 F g−1 and 760 F cm−3, respectively. Furthermore, the interpenetrating networks structure can afford rapid electron transport, and thus exhibiting excellent conductivity and good cycling stability. In addition, NIPCG assembled symmetric supercapacitor shows ultrahigh energy density of 27.6 Wh kg−1 at a power density of 600 W kg−1. Based on the above advantages, the present work holds a good potential to develop high performance energy storage and conversion devices.

Bioengineering technologies used for the development and equipment of complex installations to obtain energy from three renewable sources. Complex installations for coastal areas

Considering that the production of energy from fossil sources causes environmental pollution, increasing health hazards or climate change, the research for new alternative energy sources and the development of high-performance renewable energy conversion systems are a basic concern nowadays. Thus, the development and the use of renewable energy sources can increase diversity in energy supply markets, help to ensure long-term sustainable energy resources, to reduce local and global air emissions, and provide commercial attractive options to meet the specific needs of energy services. This paper aims to improve the efficiency of a patented complex installation which was developed vertically to ensure high-energy efficiency in relation to the occupied area, that integrates three renewable energy sources (wind, solar and hydro), by applying bioengineering solutions. Improvements to the original installation consisted in modifying the initial characteristics of the off-shore system (number of slots, deflectors angle, width of slots and width of deflectors), modification of aerial module blades according to the bioengineering model of the thistle seed (Carduus nutans), and modification of the submerged module paddies according to the bioengineering model of a fish species swimmers. Following the tests performed on the modified complex installation, a major improvement of the energy efficiency compared to the (initial) control installation was observed.

P-doped cobalt carbonate hydroxide@NiMoO4 double-shelled hierarchical nanoarrays anchored on nickel foam as a bi-functional electrode for energy storage and conversion

The rational structure design and controllable surface modification of electrode materials plays a decisive role in constructing high performance energy storage and conversion devices. Herein, the P-doped cobalt carbonate hydroxide@NiMoO4 (P-CoCH@NiMoO4) nanowires@nanosheets double-shell hierarchical structure is successfully fabricated on nickel foam. The unique nanowire@nanosheet structure with gradient porous distribution and hydrophilic nature can facilitate both the charge and electron transfer based on the synergetic effects with conductive NiMoO4 array. Importantly, the dopant of P element can enrich oxygen vacancies on the surface of CoCH nanowire, thus increase the effective active sites and enhance the electrocatalytic performance. Therefore, when act as the supercapacitor electrode, the bi-functional P-CoCH@NiMoO4/NF material achieves high areal capacitance (5.08 F cm−2 at 2 mA cm−2, 0.75 mAh cm−2) and good cyclic stability (82.7% capacitance retention after 2000 cycles). Meanwhile, when utilize as the hydrogen evolution electrode in alkaline solution, a low overpotential (115 mV at 10 mA cm−2) and Tafel slope (113.5 mV dec−1) can also be achieved.

High-performance three-body near-field thermophotovoltaic energy conversion

Three-body structures have shown great potentials in enhancing the heat transfer rate and tuning radiation spectrum in the near-field region, whereas are rarely considered in improving near-field radiative energy conversion performance. Here, a three-body thermophotovoltaic system configured by a tungsten emitter, a metallic spectrum control layer, and an In0.18Sb0.82Ga photovoltaic cell is considered. By parameter optimization of the spectrum control layer, the efficiency and output power at the gap distance of 10 nm are enhanced from 24.7% and 1.88×105 W/m2 to 35.3% and 3.62×105 W/m2, respectively. The potential mechanism lies in the excitation of coupled surface plasmon polaritons of the metallic spectrum control layer. This work paves the way for applications of three-body structure in thermophotovoltaic systems and designing high-performance energy conversion systems.

Recent advances in screening two-dimensional materials for high-performance energy storage and conversion devices based on electronic structure theory

With the ever-growing global energy demands and environmental pollution issues, developing high-performance energy storage and conversion materials has become a hot topic in the material science community. In this regard, substantial progress has been made in theoretically predicting new materials for energy-related fields, experimentally synthesizing these materials, and further improving their properties for high performance in energy storage and conversion devices. In particular, two-dimensional (2D) materials have shown great potential in the field of energy storage and conversion. However, it remains challenging to explore 2D materials that render high efficiency of energy storage and conversion while guarantee long-term stability and safety. Over the past decades, theoretical calculations based on density functional theory (DFT) have become a practical toolkit to address this issue by revealing the reaction mechanism at an atomic scale and screening high-performance energy storage and conversion materials on a large scale. In particular, DFT calculations enable us to establish the relationships between the intrinsic properties of materials and their performance for energy storage and conversion, and provide theoretical guidance for screening and experimentally synthesizing the promising materials. In this review, we summarize the DFT calculations’ applications in recent studies of developing high-performance and reliable energy-related 2D materials for Li-ion battery (LIB), water splitting, fuel cells, and electrochemical carbon dioxide reduction (CRR). First, we introduce the reaction mechanism of LIB, hydrogen evolution reaction (HER), oxygen evolution reaction/oxygen reduction reaction (OER/ORR), and CRR in detail and the application of 2D material in these fields. Then, we highlight the role of DFT calculations in unveiling the intrinsic relationships between the electronic structure and the performance of 2D materials by comprehensively discussing the descriptors in predicting the performance of 2D materials. For example, the occupancy of d orbital and energy required to fill empty states serve as descriptors to predict the electrochemical performance of the electrode in ion intercalation battery. The d orbital center, lowest unoccupied states, and oxygen vacancy formation energy serve as descriptors to predict the catalytic performance of electrode in HER. The energy difference between the lowest valance electron orbital center and Fermi level, occupancy of p z orbital, and the energy difference between p z and p x /p y orbital center serve as descriptors to predict the catalytic performance of electrode in ORR. Even though these descriptors can help to further understand the relationships between the electronic structure and the performance of the electrochemical electrode, they are only reliable to specific materials and inapplicable to the electrode with a complex structure or complex reaction path, such as the electrode in CRR. Newly developed machine learning methods may bring a breakthrough to the exploration of a universal descriptor, which is a key factor in the large-scale screening of potential electrode materials with excellent performance and the dependable guidance to experimental synthesis. Finally, we summarize the disadvantage of DFT calculation, such as the underestimation of bandgap and incorrect description of van der Waals interaction, and give a perspective of DFT calculations in the study of new energy-related materials. The method to simulate the ambient environment of the electrode (including the electrolyte, external electric field, and non-cooperative transfer of proton and electron) based on DFT calculation is needed to be developed, which is vital to reflect the actual working condition of the electrode. The universal descriptor applicable to the electrode with a complex structure is also needed to explore to overcome the poor versatility of single intrinsic property of the material in predicting the performance of the electrochemical electrode.

Facile fabrication of carbon materials with hierarchical porous structure for high-performance supercapacitors

Compared with bulk materials, porous electrodes possess superior supercapacitive performance due to the effective enlarged specific surface areas, which have aroused tremendous attention in recent years. In this work, porous carbon materials derived from glucose were facilely fabricated via a hydrothermal pre-carbonisation-calcination strategy using sodium dodecyl sulfate (SDS) as the dispersant and ZnCl2 as the activation agent. Benefitting from the uniform dispersion of SDS and the activation effect of ZnCl2, the optimised sample, SAGC-1-4, possesses a hierarchical porous structure with large specific surface area (2360 m2 g−1) and huge total pore volume (1.241 cm3 g−1), leading to an enhanced supercapacitive performance. As a result, SAGC-1-4 presented a specific capacitance of 303.02 F g−1 at 1.0 A g−1 in the three-electrode configuration. Meanwhile, the SAGC-1-4-based symmetric supercapacitor displayed an excellent rate performance with a high energy density of 31.59 Wh kg−1 at a power density of 400.00 W kg−1 in comparison with many carbon materials previously reported. Thus, our work offers an effective strategy for the fabrication of porous carbon for high-performance energy conversion and storage devices.

Tissue paper-derived porous carbon encapsulated transition metal nanoparticles as advanced non-precious catalysts: Carbon-shell influence on the electrocatalytic behaviour

Porous carbon encapsulated non-precious metal nanocatalysts have recently opened the ways towards the development of high-performance water remediation and energy conversion technologies. Herein, we report a facile, scalable and green synthetic methodology to fabricate porous carbon encapsulated transition metal nanocatalysts (M@TP: M = Cu, Ni, Fe and Co) using commercial tissue paper. The morphology, crystalline structure, chemical composition and textural properties of the M@TP nanocatalysts were thoroughly characterized. The catalytic activity of the M@TP nanocatalysts was investigated for the degradation of Congo red (CR) via peroxymonosulfate activation. Co@TP-6 was found to be the most active catalyst allowing 97.68% degradation in 30 min with a higher rate constant of 0.109 min−1. The nanocatalysts also displayed a carbon shell thickness-dependent electrocatalytic hydrogen evolution reaction (HER) activity, most likely due to the shielding effect of the carbon layers over the electron transfer (ET) processes at the metal core/carbon interfaces. Remarkably, the Ni@TP-6 electrocatalyst, with the smaller carbon shell thickness, showed the best electrocatalytic performance. They delivered an ultralow onset potential of −30 mV vs RHE, an overpotential of 105 mV at a current density of 10 mA·cm−2 and an excellent electrochemical stability to keep the 92% of the initial current applied after 25000 s, which is comparable with the HER activity of the state-of-the-art Ni-based catalysts.

Non-doped CeO2-carbonate nanocomposite electrolyte for low temperature solid oxide fuel cells

CeO2 is an oxygen nonstoichiometric material for the coexistence of redox pair of Ce3+ and Ce4+, even under an oxidizing atmosphere, and its self-doping is fulfilled bases on the multivalence characteristics. It has been served in versatile applications, including fuel cells and catalysis. Excellent electrochemical performances of solid oxide fuel cell (SOFC) have been achieved at intermediate and low-temperature range based on doped cerium oxide electrolyte. In this study, we utilize its self-doping form to prepare core-shell structure bi-phase nano-composite of CeO2 and alkali carbonate (Li2CO3, Na2CO3 and K2CO3) through a two-step synthesis method. SEM, TEM, XRD, and EIS measurements were applied to characterize the morphology, crystal size, the ionic conductivity of the electrolyte, and the electrochemical performance of resulting ceramic fuel cells. An exceptional ionic conductivity of 0.34 S cm−1 was generated at 550 °C in air, significantly different from its insulating property of the perfect CeO2 phase. A power density of 910 mW cm−2 was also achieved as the highest electrochemical performance of a single cell. The multi-ionic conduction behavior of CeO2-carbonate is also discussed. The results reveal an effective approach to develop alternative SOFC electrolyte materials for low-temperature, high-performance energy conversion applications.

Flexible PVDF based piezoelectric nanogenerators

Confronting the depletion of fossil energy and the pollution of chemical batteries, together with the rapid development of various portable electronic devices and the Internet of Things (IoT), there is an urgent requirement to develop high-performance, lightweight, and sustainable energy conversion and power supply devices. Currently, the flexible piezoelectric nanogenerator is a favourable candidate, which can be integrated with personal electronics and wireless sensors to realize sustainable energy for working with long time due to their excellent mechanical properties, good environmental adaptability and outstanding energy harvesting performance. Poly(vinylidene fluoride) (PVDF) and its copolymers, as the most flexible piezoelectric polymer materials, have been widely concerned and become the research hotspot because of their excellent flexibility, strength, easy processing and low cost. To date, significant progress has been made for PVDF based nanogenerators considering improving the output performance to meet the requirement of adapting to complex vibration environments (in vivo or in vitro). Hence, a critical review is presented to systematically summary the recent advance of flexible PVDF based piezoelectric nanogenerators in the aspects of incorporating various nanofillers, structural design, optimizing fabrication techniques and energy harvesting application. Finally, some existing challenges and future perspectives are outlined and discussed to facilitate the development of flexible piezoelectric PVDF based nanogenerators. It is hoped that this review can help researchers to gain a better overall understanding of this field and push forward it to a new stage.

Manipulating the Optoelectronic Properties of Quasi-type II CuInS2/CdS Core/Shell Quantum Dots for Photoelectrochemical Cell Applications.

Colloidal core/shell heterostructured quantum dots (QDs) possessing quasi-type II band structure have demonstrated effective surface passivation and prolonged exciton lifetime, leading to enhanced charge separation/transfer efficiencies that are promising for photovoltaic device applications. Herein, we synthesized CuInS2 (CIS)/CdS core/shell heterostructured QDs and manipulated the optoelectronic properties via controlling the CdS shell thickness. The shell-thickness-dependent optical properties indicate the existence of a quasi-type II band structure in such core/shell QDs, which was verified by ultrafast spectroscopy and theoretical simulations. These quasi-type II core/shell QDs having various shell thicknesses are used as light absorbers for the fabrication of solar-driven QDs-based photoelectrochemical (PEC) devices, exhibiting an optimized photocurrent density of ∼6.0 mA/cm2 and excellent stability under simulated AM 1.5G solar illumination. The results demonstrate that quasi-type II CIS/CdS core/shell heterostructured QDs with tailored optoelectronic properties are promising to realize high-performance QDs-based solar energy conversion devices for the production of solar fuels.

Composition tunable hollow CoAuPdPt nanospheres with enhanced catalytic properties for methanol/ethanol electrooxidation

In this report, the noble-metal-based multicomponent CoAuPdPt hollow nanospheres (MHNs) with adjustable Co/Au/Pd/Pt ratios have been constructed via a simple and reproducible strategy by using Co nanoparticles as the template based on galvanic replacement. All of the resultant CoAuPdPt MHNs show much better catalytic performance for the methanol/ethanol electrooxidation reactions than that of Pt black. For the methanol electrooxidation reaction, Co45Au28Pd57Pt27 MHNs show the highest catalytic activity and best stability. In contrast, Co41Au30Pd28Pt57 MHNs afford the best performance for the ethanol electrooxidation. The remarkable performance of the as-synthesized CoAuPdPt MHNs can be attributed to the hollow nanosphere structure as well as the synergistic effects among the Co, Au, Pd and Pt. Moreover, the catalytic activity of these catalysts can be further optimized by effectively regulating and controlling their element compositions. Hence, this work demonstrates a feasible approach for the fabrication of promising electrocatalysts to be applied in high-performance energy conversion devices and equipments.

Enhanced electrocatalytic oxygen evolution activity in geometrically designed SrRuO3 thin films

For generation of sustainable, clean and highly efficient energy, the electrocatalytic oxygen evolution reaction represents an attractive platform, thus inviting immense research activities in recent years. However, designing the catalyst with enhanced electrocatalytic activity remains one of the major challenges. Here, we examined the oxygen evolution reaction activities of geometrically designed (with and without step-textured morphology) thin films of an electrocatalytically active correlated metallic SrRuO3 perovskite grown on c- and r-plane sapphire substrates. On c-plane sapphire, as compared to the uniform surface, the step-textured films endowed with active Ru-sites show remarkable decrease in the overpotential (~25 mV). Interestingly, the behavior is opposite for the r-plane case, highlighting the significance of the active sites, in addition with the polar surface termination of selective crystal facets. Density functional theory calculation confirms the favorable energy reaction pathway for the active site dependent enhancement in OER. Our strategy might pave the way towards designing the surfaces of various oxide thin films for high performance energy conversion based devices.

Structurally stable ultrathin 1T-2H MoS2 heterostructures coaxially aligned on carbon nanofibers toward superhigh-energy-density supercapacitor and enhanced electrocatalysis

Metallic 1T MoS2 is a promising anode candidate for supercapacitors due to its intrinsically excellent electrical conductivity and high electrochemical activity. However, it is quite unstable and hard to be massively synthesized through common methods. Herein, structurally stable ultrathin (1–3 layers) in-plane 1T-2H MoS2 heterostructures have been rationally modulated and coaxially aligned on three-dimensional carbon nanofibers (MoS2/CF) through a facile hydrothermal approach for supercapacitors and electrocatalysis. Benefiting from the unique heterostructure, the MoS2/CF composite shows amazing stability with no obvious change after being stored in air for over 36 months. In addition, it presents high specific capacitance of 310 F g−1 and remarkable rate capability of 78% at 100 mV s−1. The fabricated asymmetric supercapacitor delivers an impressive energy density of 81.4 Wh kg−‍‍‍‍‍1 in 1 M Na2SO4 solution attributed to the high specific capacitance and large operating voltage range of 2 V. Moreover, the MoS2/CF composite also demonstrates enhanced electrocatalytic activity for hydrogen evolution reaction with a low overpotential of 194 mV at 10 mA cm−2. The work may promote the developments of high-performance bifunctional energy conversion and storage systems in future.

Lead-free (Ag,K)NbO3 materials for high-performance explosive energy conversion.

Explosive energy conversion materials with extremely rapid response times have broad and growing applications in energy, medical, defense, and mining areas. Research into the underlying mechanisms and the search for new candidate materials in this field are so limited that environment-unfriendly Pb(Zr,Ti)O3 still dominates after half a century. Here, we report the discovery of a previously undiscovered, lead-free (Ag0.935K0.065)NbO3 material, which possesses a record-high energy storage density of 5.401 J/g, enabling a pulse current ~ 22 A within 1.8 microseconds. It also exhibits excellent temperature stability up to 150°C. Various in situ experimental and theoretical investigations reveal the mechanism underlying this explosive energy conversion can be attributed to a pressure-induced octahedral tilt change from a - a - c + to a - a - c -/a - a - c +, in accordance with an irreversible pressure-driven ferroelectric-antiferroelectric phase transition. This work provides a high performance alternative to Pb(Zr,Ti)O3 and also guidance for the further development of new materials and devices for explosive energy conversion.

Facile synthesis of carboxylated-graphene nanosheets supported PtRu catalysts and their electrocatalytic oxidation of methanol

In this paper, we prove an efficient and facile synthesis method for preparing PtRu nanoparticles (NPs)/graphene nanosheets (GNS) catalysts for methanol electrooxidation. Our approach employed carboxylated-graphene nanosheets (C-GNS) as the support which prepared by the Friedel-Crafts reaction between succinic anhydride and GNS. The reaction conditions are mild without cumbersome pretreatment of GNS. The morphology and component of PtRu NPs/C-GNS catalysts were characterized by transmission electron microscopy (TEM) and inductively coupled plasma-atom emission spectroscopy (ICP-AES), respectively. The TEM observation reveals that PtRu NPs with an average diameter of ca. 4.0 ± 0.5 nm uniformly distributed on the edges and wrinkles of C-GNS. The further electrochemical characterizations including cyclic voltammograms (CV) and chronoamperometry (CA) methods show that PtRu NPs/C-GNS catalysts have significantly higher electrocatalytic activity and stability toward methanol electrooxidation compared to the PtRu catalysts supported on the unmodified GNS. This provides an easy approach to synthesize GNS-based electrode materials for high-performance energy conversion devices in the future.

Copper phosphosulfides as a highly active and stable photocatalyst for hydrogen evolution reaction

Transition-metal phosphosulfides (TMPSs) have recently shown outstanding electrocatalytic performances toward hydrogen evolution reaction (HER), superior to the sulfide and phosphide counterparts. However, there are only limited TMPSs available due to the synthetic challenge. Herein, we demonstrate a novel synthetic approach for copper phosphosulfide (CuPS) and the first application in photocatalytic HER. Based on the thermodynamic considerations of starting materials, two synthetic routes are designed to obtain two distinct crystal structures (CuS|P and Cu3P|S). Dramatically enhanced photocatalytic HER activities are achieved for both Cu3P|S (2,085 μmol g-1 h-1) and CuS|P (976 μmol g-1 h-1) without using co-catalysts. First-principles calculations unveil the underlying mechanism for the improved HER activity, in which the Gibbs free energy of hydrogen adsorption approaches close to 0 eV and the number of active sites considerably increases with the formation of CuPS structure. This work provides new insight and design principle on preparing TMPSs for high-performance energy conversion applications.

Ni and Zn co-substituted Co(CO3)0.5OH self-assembled flowers array for asymmetric supercapacitors

The supercapacitive performance of high-rate capacity and long-term cycling stability is still a big challenge for electroactive materials. Herein, Ni and Zn co-substituted Co carbonate hydroxide (NiZn-CoCH) flowers array is self-assembled on nickel foams (NFs) using l-ascorbic acid as a nanostructure inducer. The NiZn-CoCH flowers, consisting of silk-like nanosheets, are deservedly large electrode-electrolyte contact area and suitable ion-diffusion channel. The nanostructure and Ni and Zn co-substitution significantly improve energy storage performance. This electrode exhibits a high specific capacitance of 2020.8 F g−1 at 1 A g−1 with high-rate capacity (remain 80.2% at 10 A g−1) and 5000-cycle stability (almost unchanged after 1500 cycles at 10 A g−1). Additionally, an assembled asymmetric supercapacitor (ASC) device of NiZn-CoCH//activated carbon (AC) achieves a high energy density of 29.6 Wh kg−1 at a power density of 375 W kg−1 and only a 0.5% decrease of the capacitance after 2500 cycles. This facile and novel preparation method, using l-ascorbic acid, may be promising for industrial production of electroactive materials for the high-performance energy storage and conversion devices.

Energy cooperation in quantum thermoelectric systems with multiple electric currents**Project supported by the National Natural Science Foundation of China (Grant Nos. 11675116 and 11704093), the Jiangsu Specially-Appointed Professor Funding, and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), China.

The energy efficiency and output power of a quantum thermoelectric system with multiple electric currents and only one heat current are studied. The system is connected to the hot heat bath (cold bath) through one terminal (multiple terminals). In such configurations, there are multiple thermoelectric effects coexisting in the system. Using the Landauer–Büttiker formalism, we show that the cooperation between the two thermoelectric effects in the three-terminal thermoelectric systems can lead to markedly improved performance of the heat engine. Such improvement also occurs in four-terminal thermoelectric heat engines with three output electric currents. Cooperative effects in these multi-terminal thermoelectric systems can considerably enlarge the physical parameter region that realizes high energy efficiency and output power. For refrigeration, we find that the energy efficiency can also be substantially improved by exploiting the cooperative effects in multi-terminal thermoelectric systems. All these results reveal a useful approach toward high-performance thermoelectric energy conversion in multi-terminal mesoscopic systems.

Improved osmotic energy conversion in heterogeneous membrane boosted by three-dimensional hydrogel interface

The emerging heterogeneous membranes show unprecedented superiority in harvesting the osmotic energy between ionic solutions of different salinity. However, the power densities are limited by the low interfacial transport efficiency caused by a mismatch of pore alignment and insufficient coupling between channels of different dimensions. Here we demonstrate the use of three-dimensional (3D) gel interface to achieve high-performance osmotic energy conversion through hybridizing polyelectrolyte hydrogel and aramid nanofiber membrane. The ionic diode effect of the heterogeneous membrane facilitates one-way ion diffusion, and the gel layer provides a charged 3D transport network, greatly enhancing the interfacial transport efficiency. When used for harvesting the osmotic energy from the mixing of sea and river water, the heterogeneous membrane outperforms the state-of-the-art membranes, to the best of our knowledge, with power densities of 5.06 W m−2. The diversity of the polyelectrolyte and gel makes our strategy a potentially universal approach for osmotic energy conversion.

“One for two” strategy to prepare MOF-derived NiCo2S4 nanorods grown on carbon cloth for high-performance asymmetric supercapacitors and efficient oxygen evolution reaction

Metal-organic frameworks (MOFs) have recently emerged as promising hierarchical structured porous materials for high-performance energy storage and conversion devices due to their unique tunable structure and excellent porosity. Herein, we reported a “one for two” strategy to prepare NiCo2S4 nanorods directly grown on carbon cloth (NiCo2S4@CC) via a simply modified MOFs-derived approach for high-performance asymmetric supercapacitors and efficient oxygen evolution reaction (OER). As an electrode for asymmetric supercapacitors, the NiCo2S4@CC electrode showed excellent electrochemical performance with high specific capacitance and good rate capability. The asymmetric supercapacitor using NiCo2S4@CC as a cathode electrode and N-doped porous carbon nanosheets grown on the CC (NC@CC) as an anode electrode achieved a superior energy density and power density and a long cycle life. Furthermore, the NiCo2S4@CC exhibited a notable electrocatalytic activity as an electrocatalyst for OER. The remarkable electrochemical performance of as-prepared NiCo2S4@CC could be mainly attributed to its hierarchical structure, sufficient active sites and low metal-anion bond energy after sulfuration reaction. This work could provide an unprecedented opportunity to fabricate functional materials under rational design for various applications.