environmental friendliness, mechanical stability, simple preparation process, high efficiency, and the ability to operate at wide angle. [1][2][3] Generally, the DSSC with a sandwich-type structure is mainly composed of photoanode, dye sensitizer, electrolyte, and counter electrode (CE). [4][5][6] At present, the DSSCs with exceeded 14% photoelectric conversion efficiency are considered a favorable choice to the silicon solar cells. [7][8][9] However, the rareness and insufficient stability in I − /I 3 − electrolyte of the platinum (Pt) CE makes the DSSCs unsuitable for large-scale applications. [10,11] To address these challenges, it is very necessary to develop earth-abundant, highly catalytic activity, environment friendly, prefect conductivity, and outstanding electrochemical stability Pt-free CE catalytic materials. Currently, the carbon materials, conductive polymer, transition metal compounds, metal selenides, carbides, sulfides, and so on have attracted wide attentions. [12][13][14][15][16][17][18][19][20][21] Compared with above-mentioned reported Pt-free CE catalysts, transition metal phosphides are rare-reported but very suitable for the development of Pt-free CE in DSSCs. [22][23][24] Moreover, transition metal phosphides are a kind of important multicomponent metal/ nonmetal catalysts. Their composition usually presented as ternary or quaternary compounds or complexes have been widely used in various electrocatalysis applications such as water decomposition and oxygen reduction reaction derived from their unique advantages of earth-rich, adjustable chemical composition, excellent catalytic activity, low-cost, chemical inertness, and prefect conductivity. [25,26] Particularly, tungsten phosphide (WP) has unique physical and chemical properties including high electron transfer rate, excellent catalytic activity, and good electrocatalysis stability, and shows excellent performance in electrochemical catalytic reaction. Zhang et al. synthesized WP particles by a self-exothermic reduction strategy, which exhibited high catalytic activity and long-lasting stability with a low Tafel slope of 52 mV•dec −1 . [27] Son et al. obtained two morphologies of FeP and FeP 2 nanowires to achieve excellent hydrogen evolution reaction (HER) efficiency in acid-base environments. [28] Pi et al. fabricated WP 2 nanosheets on graphite paper using a pulsed laser deposition technique and in-situ phosphorylation, achieving the most promising efficiency as a HER cathode. [29] On the basis of outstanding performance of WP in electrocatalysis, it is expected to be potential CE candidates in The development of low-cost, green, and pollution-free counter electrode materials with high catalytic activity plays a critical role in improving the photovoltaic performance of dye-sensitized solar cells (DSSCs). In recent years, transition metal phosphides have been widely used in DSSCs due to their outstanding catalytic activity and stability. Herein, a novel binary phosphide is immobilized on carbon paper (CP) by a two-step strategy. This...