Center, zoom and type attributes are required to create a map.
<script src="https://maps.google.com/maps/api/js?key=AIzaSyCvCDkYieuUBmMWon_mfLAfjuaeuosuqow&sensor=true"></script>
<div class="card">
<p:gmap center="41.381542, 2.122893" zoom="15" type="HYBRID" style="width:100%;height:400px"/>
</div>