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The accurate identification of host mineral and the formation stage of fluid inclusions are critical to temperature measurement, and the combination of inclusion technology and other technologies could be better to figure out the source and properties. Vug fillings in Middle Permian Qixia Formation of western Sichuan Basin are characterized by the intimate intergrowth of saddle dolomite and calcite. In this paper, Alizarin Red S is successfully used to distinguish the host minerals of fluid inclusions on the basis of the recognition of the sequence of diagenetic authigenic minerals. The results show that the Alizarin red staining techniques used in measuring fluid inclusion temperature of carbonates is feasible due to the difference of homogenization temperature of fluid inclusions before and after Alizarin Red staining is within 1℃. Solution proportion (especially the concentration of hydrochloric acid), dyeing time and the clearing way of staining solution are key parameters to the application of Alizarin red staining technique on the temperature measurement of fluid inclusion. Fluid-inclusion homogenization temperature of saddle dolomite mainly range from 110℃ to 190℃, up close to 270℃, and that of calcite is mainly between 70℃ and 130℃. Formation temperature difference of about 40-60℃ between saddle dolomite and calcite may be related to the Emeishan basalt eruptions in the late Permian. Fluids with high temperature related to the Emeishan basalt eruptions overcome the dolomite precipitation kinetics barrier and cause saddle dolomite precipitated. Saddle dolomite was dissolved and calcite precipitated in the dissolution space of dolomite and inter-granular pores due to the decrease of paleo-temperature after the thermal event.

Exploring highly active oxygen reduction electrocatalysts with low precious metals content is imperative but remains a considerable challenge. Herein, a series of heterobimetallic multi-walled carbon nanotubes (MWCNTs) electrocatalysts based on metal complexes are presented. These electrocatalysts feature diverse transition metals (M=Mn, Fe, Co, Ni) 5,15-bromophenyl-10, 20-methoxyphenyl porphyrin (MBMP) and tetrakis(triphenylphosphine)palladium (0) (Pd[P(Ph 3 ) 4 ]) anchored non-covalently on its surface. The resulting NiBMP-based MWCNTs with Pd[P(Ph 3 ) 4 ] (PdNiN4/MWCNTs) display outstanding electrocatalytic oxygen reduction activity (onset potential, 0.941 V; half wave potential, 0.830 V) and robust long-term durability in alkaline electrolyte. While in neutral condition, the MnBMP-based MWCNTs with Pd[P(Ph 3 ) 4 ] (PdMnN4/MWCNTs) are the most active heterobimetallic ORR catalyst and produce ultra-low concentration hydrogen peroxide (H 2 O 2 yield, 1.2%-1.3%). Synergistically tuning the ORR electrocatalytic activity and electron transfer pathway is achieved by the formation of NiBMP/MnBMP-Pd[P(Ph 3 ) 4 ] active sites. This work indicates such metalloporphyrin-Pd[P(Ph 3 ) 4 ] active sites on MWCNTs have significantly positive influence on electrocatalytic ORR systems and provides facile and mild strategy for designing highly efficient ORR electrocatalysts with ultra-low loading precious metal., (© 2023 IOP Publishing Ltd.)