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These days, Beijing is once again shrouded in compound fog, with endless complaints. Today, I’ll talk to you about the challenges and \"embarrassing situations\" behind this fog. Although the sources of fog and haze are not limited to human activities, it is undeniable that the majority of these phenomena are caused by the burning of fossil fuels. In today’s energy structure, despite the rapid development of new energy sources in recent years, traditional fossil fuels still account for over 80% of the total energy use. Their continuous combustion leads to severe environmental pollution as well as an increasingly serious greenhouse effect. The non-renewable nature of fossil fuels represents a major challenge for humanity, and the only solution is to develop clean energy sources. Not long ago, a research team from Tsinghua University in our country developed a \"WS2/WO2.9/C\" composite film with a custom-designed self-supporting structure, which was used as a high-performance electrocatalytic hydrogen evolution electrode. The researchers prepared this thin film material on graphite paper using simple spin-coating and heat-treatment processes. This composite film is composed of WS2 nanosheets and WO2.9 nanowires embedded in a conductive carbon substrate. The embedded structure exposes the edge sites of catalytically active WS2 nanosheets on the film surface, thereby reducing the contact resistance in small-molecule technologies. Due to the introduction of trace amounts of oxygen during the heat treatment process, metallic WO2.9 nanowires were formed, and the WS2/WO2.9 heterojunction further enhanced the electrical conductivity. Furthermore, sulfur vacancies were formed in the basal plane at the center of the WS2 layers, **which enhanced the catalytic activity, and WO2.9 also exhibits certain catalytic activity. Due to the synergistic effect of WS2 and WO2.9, the \"WS2/WO2.9/C\" composite film exhibits excellent hydrogen evolution catalytic activity: the hydrogen evolution overpotential is 20 mV, and the Tafel slope is 36 mV/dec, which is already very close to the performance of Pt/C electrodes. The mosquito net information comes from Molfind website (www.molfind.cn)