Weimo Li

Bio: Weimo Li is an academic researcher from Jilin University. The author has contributed to research in topics: Electrocatalyst & Water splitting. The author has an hindex of 5, co-authored 7 publications receiving 130 citations.

RuNi Nanoparticles Embedded in N-Doped Carbon Nanofibers as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting.

Abstract: Developing high-performance, low-cost, and robust bifunctional electrocatalysts for overall water splitting is extremely indispensable and challenging. It is a promising strategy to couple highly active precious metals with transition metals as efficient electrocatalysts, which can not only effectively reduce the cost of the preparation procedure, but also greatly improve the performance of catalysts through a synergistic effect. Herein, Ru and Ni nanoparticles embedded within nitrogen-doped carbon nanofibers (RuNi-NCNFs) are synthesized via a simple electrospinning technology with a subsequent carbonization process. The as-formed RuNi-NCNFs represent excellent Pt-like electrocatalytic activity for the hydrogen evolution reaction (HER) in both alkaline and acidic conditions. Furthermore, the RuNi-NCNFs also exhibit an outstanding oxygen evolution reaction (OER) activity with an overpotential of 290 mV to achieve a current density of 10 mA cm-2 in alkaline electrolyte. Strikingly, owing to both the HER and OER performance, an electrolyzer with RuNi-NCNFs as both the anode and cathode catalysts requires only a cell voltage of 1.564 V to drive a current density of 10 mA cm-2 in an alkaline medium, which is lower than the benchmark of Pt/C||RuO2 electrodes. This study opens a novel avenue toward the exploration of high efficient but low-cost electrocatalysts for overall water splitting.

Integrated transition metal and compounds with carbon nanomaterials for electrochemical water splitting

Abstract: The development of highly efficient, low-cost and robust electrocatalysts for water splitting is urgently necessary to approach the energy crisis and environmental problems. In recent years, transition metal-based materials are commonly used as outstanding electrode materials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) due to their tunable electrocatalytic activity and earth-abundance. However, they are restrained from the disadvantages of low conductivity, easy agglomeration and poor stability. Therefore, it is a good choice to integrate transition metal compounds with carbon materials to address the aforementioned issues. In this review, we focus on the recent progress of the fabrication of a variety of transition metal-based materials integrated with carbon matrices for HER, OER and overall water splitting. First, the fundamentals of the water splitting process and the introduction of parameters to determine the water splitting performance are given. Then, the advantages of the integration of transition metals and compounds with carbon for electrolytic water splitting as well as the influence of the architecture, composition, electronic structure and interface engineering of the hybrid materials on their electrocatalytic activities are discussed. The experimental and theoretical simulation are complementary to investigate the mechanism of the enhanced HER, OER and overall water splitting processes. Finally, challenges, perspectives and opportunities for developing new transition metals and carbon-based electrocatalysts in water splitting are featured.

Interface Engineering of Heterogeneous CeO2-CoO Nanofibers with Rich Oxygen Vacancies for Enhanced Electrocatalytic Oxygen Evolution Performance.

Abstract: The development of highly efficient and cheap electrocatalysts for the oxygen evolution reaction (OER) is highly desirable in typical water-splitting electrolyzers to achieve renewable energy production, yet it still remains a huge challenge. Herein, we have presented a simple procedure to construct a new nanofibrous hybrid structure with the interface connecting the surface of CeO2 and CoO as a high-performance electrocatalyst toward the OER through an electrospinning-calcination-reduction process. The resultant CeO2-CoO nanofibers exhibit excellent electrocatalytic properties with a small overpotential of 296 mV at 10 mA cm-2 for the OER, which is superior to many previously reported nonprecious metal-based and commercial RuO2 catalysts. Furthermore, the prepared CeO2-CoO nanofibers display remarkable long-term stability, which can be maintained for 130 h with nearly no attenuation of OER activity in an alkaline electrolyte. A combined experimental and theoretical investigation reveals that the excellent OER properties of CeO2-CoO nanofibers are due to the unique interfacial architecture between CeO2 and CoO, where abundant oxygen vacancies can be generated due to the incomplete matching of atomic positions of two parts, leading to the formation of many low-coordinated Co sites with high OER catalytic activity. This research provides a practical and promising opportunity for the application of heterostructured nonprecious metal oxide catalysts for high-efficiency electrochemical water oxidation.

Heterostructured Inter-Doped Ruthenium-Cobalt Oxide Hollow Nanosheet Arrays for Highly Efficient Overall Water Splitting.

Abstract: The development of transition-metal-oxides (TMOs)-based bifunctional catalysts toward efficient overall water splitting through delicate control of composition and structure is a challenging task. Herein, the rational design and controllable fabrication of unique heterostructured inter-doped ruthenium-cobalt oxide [(Ru-Co)Ox ] hollow nanosheet arrays on carbon cloth is reported. Benefiting from the desirable compositional and structural advantages of more exposed active sites, optimized electronic structure, and interfacial synergy effect, the (Ru-Co)Ox nanoarrays exhibited outstanding performance as a bifunctional catalyst. Particularly, the catalyst showed a remarkable hydrogen evolution reaction (HER) activity with an overpotential of 44.1 mV at 10 mA cm-2 and a small Tafel slope of 23.5 mV dec-1 , as well as an excellent oxygen evolution reaction (OER) activity with an overpotential of 171.2 mV at 10 mA cm-2 . As a result, a very low cell voltage of 1.488 V was needed at 10 mA cm-2 for alkaline overall water splitting.

Recent Advances in Energy Conversion Applications of Carbon Dots: From Optoelectronic Devices to Electrocatalysis

Abstract: Exploitation and utilization of sustainable energy sources has increasingly become the common theme of global social development, which has promoted tremendous development of energy conversion devices/technologies. Owing to excellent and unique optical/electrical properties, carbon dots (CDs) have attracted extensive research interest for numerous energy conversion applications. Strong absorption, downconversion photoluminescence, electron acceptor/donor characteristics, and excellent electron conductivity endow CDs with enormous potential for applications in optoelectronic devices. Furthermore, excellent electron transfers/transport capacities and easily manipulable structural defects of CDs offer distinct advantages for electrocatalytic applications. Recent advances in CD-based energy conversion applications, including optoelectronic devices such as light-emitting diodes and solar cells, and electrocatalytic reactions including the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and carbon dioxide reduction reaction, are summarized. Finally, current challenges and future prospects for CD-based energy conversion applications are proposed, highlighting the importance of controllable structural design and modifications.

Integrated transition metal and compounds with carbon nanomaterials for electrochemical water splitting

Abstract: The development of highly efficient, low-cost and robust electrocatalysts for water splitting is urgently necessary to approach the energy crisis and environmental problems. In recent years, transition metal-based materials are commonly used as outstanding electrode materials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) due to their tunable electrocatalytic activity and earth-abundance. However, they are restrained from the disadvantages of low conductivity, easy agglomeration and poor stability. Therefore, it is a good choice to integrate transition metal compounds with carbon materials to address the aforementioned issues. In this review, we focus on the recent progress of the fabrication of a variety of transition metal-based materials integrated with carbon matrices for HER, OER and overall water splitting. First, the fundamentals of the water splitting process and the introduction of parameters to determine the water splitting performance are given. Then, the advantages of the integration of transition metals and compounds with carbon for electrolytic water splitting as well as the influence of the architecture, composition, electronic structure and interface engineering of the hybrid materials on their electrocatalytic activities are discussed. The experimental and theoretical simulation are complementary to investigate the mechanism of the enhanced HER, OER and overall water splitting processes. Finally, challenges, perspectives and opportunities for developing new transition metals and carbon-based electrocatalysts in water splitting are featured.