Low-cost and resourceful transition metal phosphides (TMPs) have gradually received wide acceptance in the energy industry through exhibiting comparable catalytic activity and long-term stability to traditional catalysts (e.g., Pt/C, LiCoO2, LiFePO4, etc.). With the emergence of the research hotspot of TMPs, probing their mechanism of catalytic energy conversion and storage inspired by the superb structure of metal-phosphorus chelate is of great significance. To this end, recent developments in TMPs with various crystal structures and morphologies have attracted much attention. The design of TMPs ranging from the choice of different transition metals to phosphorus sources has been intensively explored. This research has indicated that multidimensional morphologies of TMPs prominently enrich the patterns of charge storage and electron transportation, and ultra-nanoscaled TMPs obtained by multiple tools and techniques might challenge the threshold of electrocatalytic reactions. Here, recent developments in synthetic strategies of TMPs from different precursors are classified. The underlying mechanism between the structural and crystallographic characteristics and the tuned properties of TMPs in energy applications is also presented. Additionally, the key trends in structure and morphology characterization of TMPs are highlighted. Future perspectives on the challenges and opportunities facing TMPs catalysts are thereby proposed.

Earth-Rich Transition Metal Phosphide for Energy Conversion and Storage

Platinum is one of the most important electrode materials for continuous electrochemical energy conversion due to its high activity and stability. The resistance of this scarce material towards dissolution is however limited under the harsh operational conditions that can occur in fuel cells or other energy conversion devices. In order to improve the understanding of dissolution of platinum, we therefore investigate this issue with an electrochemical flow cell system connected to an inductively coupled plasma mass spectrometer (ICP-MS) capable of online quantification of even small traces of dissolved elements in solution. The electrochemical data combined with the downstream analytics are used to evaluate the influence of various operational parameters on the dissolution processes in acidic electrolytes at room temperature. Platinum dissolution is a transient process, occurring during both positive- and negative-going sweeps over potentials of ca. 1.1 VRHE and depending strongly on the structure and chemistry of the formed oxide. The amount of anodically dissolved platinum is thereby strongly related to the number of low-coordinated surface sites, whereas cathodic dissolution depends on the amount of oxide formed and the timescale. Thus, a tentative mechanism for Pt dissolution is suggested based on a place exchange of oxygen atoms from surface to sub-surface positions.

/pdf/towards-a-comprehensive-understanding-of-platinum-exju61n4fk.pdf

Towards a comprehensive understanding of platinum dissolution in acidic media

On the enhanced corrosion resistance of a selective laser melted austenitic stainless steel

Degradation mechanisms of proton exchange membrane fuel cell under typical automotive operating conditions

Durability of platinum-based fuel cell electrocatalysts: Dissolution of bulk and nanoscale platinum

Dissolution Mechanism of Platinum in Sulfuric Acid Solution

Pit Initiation Mechanism at MnS Inclusions in Stainless Steel: Synergistic Effect of Elemental Sulfur and Chloride Ions

A Microelectrochemical System for In Situ High-Resolution Optical Microscopy: Morphological Characteristics of Pitting at MnS Inclusion in Stainless Steel

Yu Sugawara

Papers

Dissolution Mechanism of Platinum in Sulfuric Acid Solution

Pit Initiation Mechanism at MnS Inclusions in Stainless Steel: Synergistic Effect of Elemental Sulfur and Chloride Ions

A Microelectrochemical System for In Situ High-Resolution Optical Microscopy: Morphological Characteristics of Pitting at MnS Inclusion in Stainless Steel

Fabrication of nanoporous copper by dealloying amorphous binary Ti–Cu alloys in hydrofluoric acid solutions

Pit initiation on sensitized Type 304 stainless steel under applied stress: Correlation of stress, Cr-depletion, and inclusion dissolution