Volume 2 Issue 9 September 2017

Volume 2 Issue 9

Evolving catalysts evolve hydrogen

Transition metal dichalcogenides (TMDs) can be used for electrocatalytic generation of hydrogen from water. Guided by computation, Liu et al. show that high electrocatalytic activity can be achieved on the basal planes — rather than the edge sites, which are more commonly associated with high activity — of certain layered TMDs such as tantalum disulfide. The activity improves during cycling due to evolution of the catalyst morphology.

See Liu et al. 2, 17127 (2017) and News and Views by Chirdon & Wu, article 17132.

Image: Ryan Chen. Cover design: Alex Wing.

Editorial

  • Editorial |

    Energy models provide powerful insights for decision-makers, but more care is needed around the choice of reference scenarios and the transparency of assumptions.

Comment

  • Comment |

    The structure of active sites of enzymes involved in bioenergetic processes can inspire design of active, stable and cost-effective catalysts for renewable-energy technologies. For these materials to reach maturity, the benefits of bioinspired systems must be combined with practical technological requirements.

    • Vincent Artero
  • Comment |

    The Trump administration's domestic plans would have curtailed the nation's climate action even if it had stayed in the Paris Agreement. Yet, the decision to leave the agreement undermines US international energy and climate leadership and the prospects of ramping up global climate policy ambition.

    • Jason Bordoff

Research Highlights

News & Views

  • News and Views |

    Typically, the allocation of renewable power sources is determined by a desire to maximize output and reduce generation costs in order to satisfy the preferences of a small number of stakeholders. A new model broadens this perspective by considering societal equity and acceptability, with the aim of improving the siting process.

    • Philipp Grunewald
  • News and Views |

    Transition-metal dichalcogenides are appealing catalysts for H2 generation from water. They tend to rely on scarce edge sites, rather than the more abundant basal-plane sites, to drive catalysis. Now, guided by computation, H-TaS2 and H-NbS2 are proposed as highly basal-plane-active catalysts that improve with electrochemical cycling.

    • Danielle N. Chirdon
    •  & Yiying Wu
  • News and Views |

    The utilization of porous carbon cathodes in lithium–air batteries is hindered by their severe decomposition during battery cycling. Now, dual redox mediators are shown to decouple the complex electrochemical reactions at the cathode, avoiding cathode passivation and decomposition.

    • Ji-Jing Xu
    •  & Xin-Bo Zhang
  • News and Views |

    Environmental heat sinks beyond local air are available for use with normal air conditioners to increase their efficiency. A study has exploited outer space and the atmosphere as remote sinks to demonstrate daytime sub-ambient fluid cooling and its application in reducing the energy needed to cool an interior.

    • Geoff Smith
    •  & Angus Gentle

Perspective

  • Perspective |

    Despite being currently under-represented in IPCC reports, PV generation represents a growing share of power generation. This Perspective argues that underestimating PV potential led to suboptimal integration measures and that specific deployment strategies for emerging economies should be developed.

    • Felix Creutzig
    • , Peter Agoston
    • , Jan Christoph Goldschmidt
    • , Gunnar Luderer
    • , Gregory Nemet
    •  & Robert C. Pietzcker

Research

  • Article |

    The Li–O2 cell performance is largely limited by the insulating and insoluble nature of Li2O2. Here the authors report that dual mediators decouple the electrochemical reactions at the cathode from the formation and decomposition of Li2O2 from solutions, helping stabilize the carbon cathode.

    • Xiangwen Gao
    • , Yuhui Chen
    • , Lee R. Johnson
    • , Zarko P. Jovanov
    •  & Peter G. Bruce
  • Article |

    Li dendrite formation is a major obstacle in the development of Li metal batteries. Nazar and colleagues present a protection method for the Li metal by an in situ synthesis of Li-based surface alloy composites, and demonstrate promising battery applications.

    • Xiao Liang
    • , Quan Pang
    • , Ivan R. Kochetkov
    • , Marina Safont Sempere
    • , He Huang
    • , Xiaoqi Sun
    •  & Linda F. Nazar
  • Article |

    As renewable energy technology deployment continues apace, it is increasingly important to consider the optimal spatial allocation of power plants. Towards this end, Drechsler et al. employ a variety of methods to understand the most efficient and equitable distribution of solar and wind plants across Germany.

    • Martin Drechsler
    • , Jonas Egerer
    • , Martin Lange
    • , Frank Masurowski
    • , Jürgen Meyerhoff
    •  & Malte Oehlmann
  • Article |

    Electricity storage will benefit from both R&D and deployment policy. This study shows that a dedicated programme of R&D spending in emerging technologies should be developed in parallel to improve safety and reduce overall costs, and in order to maximize the general benefit for the system.

    • Noah Kittner
    • , Felix Lill
    •  & Daniel M. Kammen
  • Article |

    Metal dichalcogenides are promising electrocatalysts for hydrogen evolution, but more active and stable materials are desired. Here the authors demonstrate that H-TaS2 and H-NbS2 possess high basal-plane activity that increases with cycling through changes in the morphology of the catalysts.

    • Yuanyue Liu
    • , Jingjie Wu
    • , Ken P. Hackenberg
    • , Jing Zhang
    • , Y. Morris Wang
    • , Yingchao Yang
    • , Kunttal Keyshar
    • , Jing Gu
    • , Tadashi Ogitsu
    • , Robert Vajtai
    • , Jun Lou
    • , Pulickel M. Ajayan
    • , Brandon C. Wood
    •  & Boris I. Yakobson
  • Article |

    Various strategies are developed to combine high efficiency and stability in perovskite solar cells. Here, Wang et al. mix 2D and 3D mixed-cation and mixed-halide perovskite phases in solar cells with stabilized efficiencies up to 19.5% and improved stability under full illumination and ambient air.

    • Zhiping Wang
    • , Qianqian Lin
    • , Francis P. Chmiel
    • , Nobuya Sakai
    • , Laura M. Herz
    •  & Henry J. Snaith
  • Article |

    Radiative sky cooling passively rejects heat from a surface out into space via an atmospheric transparency window, enabling sub-ambient cooling. Goldstein et al. exploit this to show daytime cooling of water by up to 5 C below ambient temperature, equivalent to a heat rejection flux of 70 Wm−2.

    • Eli A. Goldstein
    • , Aaswath P. Raman
    •  & Shanhui Fan
  • Article |

    To improve the efficiency of photovoltaic devices while keeping the same spatial footprint, solar cells can be stacked on top of each other. Here, Essig et al. fabricate very efficient dual-junction and triple-junction solar cells by placing one or two III–V solar cells on top of a silicon solar cell.

    • Stephanie Essig
    • , Christophe Allebé
    • , Timothy Remo
    • , John F. Geisz
    • , Myles A. Steiner
    • , Kelsey Horowitz
    • , Loris Barraud
    • , J. Scott Ward
    • , Manuel Schnabel
    • , Antoine Descoeudres
    • , David L. Young
    • , Michael Woodhouse
    • , Matthieu Despeisse
    • , Christophe Ballif
    •  & Adele Tamboli
  • Analysis |

    Clean energy sources bring environmental and health benefits by reducing traditional electricity sources. Millstein et al. analyse data from 2007–2015 on the expansion of solar and wind power in the US to explore impacts in terms of air pollution, avoided emissions and associated premature mortality.

    • Dev Millstein
    • , Ryan Wiser
    • , Mark Bolinger
    •  & Galen Barbose