Resilience to tipping points in ecosystems Spatial pattern formation has been proposed as an early warning signal for dangerous tipping points and imminent critical transitions in complex systems, including ecosystems. Rietkerk et al . review how ecosystems and Earth system components can actually evade catastrophic tipping through various pathways of spatial pattern formation. With mathematical and real-world examples, they argue that evading tipping and enhancing resilience could be relevant for many ecosystems and Earth system components that until now were known as tipping prone. Many of these complex systems may be more resilient than currently thought because of overlooked spatial dynamics and multiple stable states, and may thus not undergo critical or catastrophic transitions with global change. —AMS

ferent solar driven hydrogen production approaches (i.e., photocatalyst, [4] photoelectrochemical, [5] PV [6]), where the PV part as power supply can be directly connected to the electrochemical (EC) part. [7] Although water electrolysis can be operated in any pH condition, efficient and stable catalysts made of earth-abundant materials are mostly found for strong alkaline electrolytes. [8] Among the promising candidates in alkaline electrolysis, inorganic Co-based compounds have been intensively investigated due to their reasonable performance. [9,10] Iron is relatively well known as a dopant in the Co-based catalysts, and the activity of Fe-doped Co catalysts is significantly enhanced by synergistic effects between Co and Fe. [11] Recently, it was found that the incorporation of high-valence vanadium (V) in Co-based catalysts is beneficial for the oxygen evolution reaction (OER) performance. [12] It is suggested that V doping may play a role in adjusting the electronic structure in the Co-based catalysts. In order to increase the activity of the OER catalysts also ternary CoVFe compounds have been prepared and investigated. [13] We have investigated the use of different Co-based catalysts in bifunctional configuration. A bifunctional configuration (one type of the catalyst for both, anode and cathode at the same time) offers a great potential for reducing the cost of catalyst production and thus of the entire system. [14] The composition of the binary and ternary catalysts was adjusted according to the metalhydroxide (MOH) bond strength theory. [12a,15] Each type of mixed compound was explored in both OER and hydrogen evolution reaction (HER) in the same alkaline electrolyte. We found that the sample consisting of Co 0.6 Fe 0.3 V 0.1 O x shows the best performance (at 10 mA cm −2) with an overpotential of 269 mV for HER and 266 mV for OER, respectively. An X-ray photoelectron spectroscopy (XPS) analysis has revealed that vanadium is almost completely depleted in the OER catalyst after the reaction. In combination with the Pourbaix diagram of V species, we assume that for OER vanadium does not modify the electrical property, [13b] the MOH binding energy, [12a] or the coordination environment in the mixed film [12b,16] as previously suggested. Probably the dissolution of the vanadium results in the creation of pores in the mixed catalyst that might be related to the positive Photovoltaic driven electrochemical (PV-EC) water splitting technology is considered as one of the solutions for an environmental-friendly hydrogen supply. In a PV-EC system, efficient catalysts are required to increase the rate of both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Here, the development of a CoFeVO x bifunctional catalyst produced by a simple electrodeposition method is presented. It is found that after the water splitting reaction, vanadium is almost completely depleted in the mixture of elements for OER, while its concentration at the HER catalyst is similar or even higher after the reaction. Fo...

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