Abstract: Atomically dispersed platinum-group metal-free catalyst and method for synthesizing the same. According to one embodiment, the catalyst is made by a method in which, in a first step, an Mn-doped ZIF-8 catalyst precursor is prepared by reacting a first solution comprising zinc nitrate hexahydrate and manganese chloride dissolved in an acid/water solution with a second solution comprising 2-methylimidazole dissolved in water. Then, in a second step, the Mn-doped ZIF-8 catalyst precursor is thermally activated, i.e., carbonized, to form an Mn—N—C catalyst. Preferably, the thermal activation is performed in a multistep fashion, first at a lower temperature of about 800° C. and then at a higher temperature of about 1100° C. After carbonization, the catalyst material may optionally be subjected to an absorption process, followed by a second thermal activation. The absorption process may involve dispersing the catalyst material in a solution of manganese chloride and urea in hydrochloric acid and isopropanol.

Abstract: The present invention provides a plate-fin heat exchanger core and a fin structure thereof. The plate-fin heat exchanger core includes: a plurality of partition plates and a fin, where the fin is supported and fixed between two adjacent partition plates; the two adjacent partition plates are sealed to form a fluid channel unit; the fluid channel unit forms a plurality of heat exchange channels for a medium to flow between the adjacent partition plates; the fin is provided with a plurality of dimples/protrusions; the dimple/protrusion is provided with a perforated hole to form a perforated dimple/protrusion. The fin increases the heat exchange area, and the dimple/protrusion structure improves the pressure-bearing capacity of the plate-fin structure and improves fluid turbulence, thinning a flow boundary layer and a hot boundary layer.