Perspectives on Corrosion Studies Using Scanning Electrochemical Cell Microscopy: Challenges and Opportunities

Scanning electrochemical cell microscopy (SECCM) allows for electrochemical imaging at the micro- or nanoscale by confining the electrochemical reaction cell in a small meniscus formed at the end of a micro- or nanopipette. This technique has gained popularity in electrochemical imaging due to its high-throughput nature. Although it shows considerable application potential in corrosion science, there are still formidable and exciting challenges to be faced, particularly relating to the high-throughput characterization and analysis of microelectrochemical big data. The objective of this perspective is to arouse attention and provide opinions on the challenges, recent progress, and future prospects of the SECCM technique to the electrochemical society, particularly from the viewpoint of corrosion scientists. Specifically, four main topics are systematically reviewed and discussed: (1) the development of SECCM; (2) the applications of SECCM for corrosion studies; (3) the challenges of SECCM in corrosion studies; and (4) the opportunities of SECCM for corrosion science.

Electrochemical properties of humic acid and its novel applications: A tip of the iceberg

The widely existed humic acid (HA) with abundant redox-active groups has been considered to play an important role in biogeochemistry in sediments and soils. Recent studies reported that HA showed great performance in terms of electron transfer capacity (up to HA_EDC = 94 mmol e^-/mol C, HA_EAC = 42 mmol e^-/mol C). Since HA is widely available, inexpensive and environmentally friendly, the electrochemistry of HA has been explored to apply in many fields, such as environmental remediation, detection sensor and energy storage. Whereas, these prospective applications of HA and their electrochemical principles were lack of a comprehensive summary. In this review, the electrochemical properties and the prospective electrochemical applications of HA were summarized. Simultaneously, the existing problems like shortages of traditional electrochemical characterization of HA, and future research directions about HA electrochemistry were prospected. This review provides a deeper understanding of HA electrochemistry, and also inspires ideas for environmental remediation, detection sensor and energy storage by exploring the potential application values of HA.

Scanning Ion Conductance Microscopy

Scanning ion conductance microscopy (SICM) has emerged as a versatile tool for studies of interfaces in biology and materials science with notable utility in biophysical and electrochemical measurements. The heart of the SICM is a nanometer-scale electrolyte filled glass pipette that serves as a scanning probe. In the initial conception, manipulations of ion currents through the tip of the pipette and appropriate positioning hardware provided a route to recording micro- and nanoscopic mapping of the topography of surfaces. Subsequent advances in instrumentation, probe design, and methods significantly increased opportunities for SICM beyond recording topography. Hybridization of SICM with coincident characterization techniques such as optical microscopy and faradaic electrodes have brought SICM to the forefront as a tool for nanoscale chemical measurement for a wide range of applications. Modern approaches to SICM realize an important tool in analytical, bioanalytical, biophysical, and materials measurements, where significant opportunities remain for further exploration. In this review, we chronicle the development of SICM from the perspective of both the development of instrumentation and methods and the breadth of measurements performed.